Kilobaud 1980 10

PHOI*' 1 '

debts

YOUR

family

inherit^

taxes

74470 65945

Will Fate Shortchange
Your Family’s Future?

Computerize Your Estate Planning. Pg. 31

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SINTETOC

DATA

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PLS-1 LOGIC PULSER

The PLS- 1 logic pulser will superimpose a dynamic pulse train ( 20 pps) or a single pulse onto the circuit node under
test. There is no need to unsolder pins or cut printed-circuit traces even when these nodes are being clamped by digital
outputs.

PLS- 1 is a multi-mode, high current pulse generator packaged in a hand-held shirt pocket portable instrument. It can
source or sink sufficient current to force saturated output transistors in digital circuits into the opposite logic state.
Signal injection is by means of a pushbutton switch near the probe tip. When the button is depressed, a single
high-going or low-going pulse of 2 /jl sec wide is delivered to the circuit node under test. Pulse polarity is automatic:
high nodes are pulsed low and low nodes are pulsedhigh . Holding the button down delivers a series of pulses of 20 pps
to the circuit under test.

High input impedance(off state) 1 meg ohm • Multi mode-single pulses or pulse trains
Low output impedance (active state) 2 ohms • Automatic polarity sensing

Output pulse width 2 nsec nominal • Automatic cun ent limiting; 7 amps nominal
Input over voltage protection +50 volts • Automatically programmed output level
Finger tip push button actuated • Circuit powerec
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Multi-family RTL, DTL, TTL, CMOS, MOS and Mi coprocessors.

PRB 1 DIGITAL LOGIC PROBE $ 36.95 PA 1 HIGF ' VOLTAGE ADAPTER $ 8.80

PCI POWER CORD, Alligator Clips $ 4.98 PT 2 REPLACEMENT PROBE TIP (2) $ 1.80

PC 2 POWER CORD, Micro Hooks $ 9.98 PLS 1 LOGIC PULSER $ 48.98

OK Machine & Tool Corporation

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Tel. (2 12) 994-6600 Telex 125091

* Minimum billings $25.00, add shipping charge $2.00
New York State residents add applicable! tax

4 Microcomputing, October 1980

micro info

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\

kilobaud

MICROCOMPUTING™

contents' October ’80

ARTICLES

31 Computerized Estate Planning OSI program to settle your wealth. James Owens
36 5 Conversing with Your Computer Call your computer by phone. Marc Seligman

40 Address List Program Machine-language program for 6800 users. C. H. Looney
50 Upgrading the Heath H8 with a Z-80 The HZ8 adapter. Patrick Swayne
56 Level II ROM Subroutine Test Talking to your TRS-80. Robert M. Richardson
60 Kilobaud Klassroom No. 21 Expansions and Programming. Peter A. Stark
72 What Is the Utility of a Utility? Information at low cost. Frank J. Derfler, Jr.

75 Darkroom Computerist A picture-perfect way to use your SWTP. Marc I. Leavey, M.D.

82 Start/Exit Routine for CP/M Orderly linkages between CP/M and user programs. Ken Barbier
84 Modifying the Horizon Double Density DOS Personalize your system. George L. Haller
88 PET Mini Monitor Saving machine-language programs is a snap. William H. Perdue
92 Computer-Controlled Triac Dimmer a light project. Merrill Lessiey
102 1 OSI in the Sky A heavenly approach to handle subscriptions. William E. Shawcross, Roger W. Sinnott

106 A New Branch on the Family Tree The nscsoo. Ken Barbier
112 Area Estimation It’s a matter of BASIC geometry. Arnold W. Bragg

117 The SWTP Computer System Topics include the 6809, multiprogramming and interrupts. Peter A. Stark

128 Speed Up Your BASIC Programs Simple techniques make a difference. Edward H. Carlson

132 Whoa, Apple Tightening the reins on galloping video displays. Terry Edward Phillips

136 Cassette Format for 6800 Systems Speed improvement for the KC Standard. Dr. Gordon W. Wolfe

142 Exploring CT-82 Graphics SWTP video terminal revealed. Phil Hughes

154 Tracking Down the Bus Why some boards won’t work with the S-100. Richard A. Rodman

158 Dial-up Directory Meet Forum-80 founder, Bill Abney. Frank J. Derfler, Jr.

162 Reduce Search Time with an Index Breeze through file searches. LeRoy E. Kolderup
168 Video HARDCOPY for CP/M Instant printing power. Glenn Stok

174 Bridging the 1 pF to 100,000 uF Gap Inexpensive digital capacitance meter. Robert J. Stetson
180 Betting on Old POKEy Animated graphics on your PET. Gary Greenberg
182 The 16-Bit Time Trials Benchmarks revisited. Allan Flippin

192 1802 Machine-Language Techniques Puts zip in your vip. Gerald strope

196 Poor Man’s Logic Analyzer Troubleshooting on a shoestring. Scott B. Eckert

202 A Humanist’s Approach to Computer Programming a man is his program. Dick Lutz

208 Overlay Programming Memory-saving technique. Robert A. Peck

210 A Roundoff Function in Applesoft Keep your numbers manageable. Barton M. Bauers, Jr.

212 Clock Control Board Speed up your TRS-80. . .elegantly. Mark A. Schimelman, M.D.

DEPARTMENTS

Publisher’s Remarks — 6
PET-pourri-12
Computer Blackboard — 16
Book Reviews — 18
Micro Quiz -19

New Products -20
New Software -23
Letters to the Editor -27
Dealer Directory — 214
Classifieds -214

Cover photo by Reese Fowler.

Microcomputing, October 1980 5

Wayne Green

PUBLISHER’S REMARKS

Five Years Ago,
Five Years Hence

The microcomputer industry is just five years
old this year, yet it has already seen some spec-
tacular changes— and more are to come. In
1975 Mits introduced the first microcomputer
kit to attract widespread attention. Before that,
several small firms had kits using the 8008 chip,
but the interested numbered in the hundreds
rather than the thousands. It took Mits to break
things loose.

By the end of that first year, Mits had been
joined by Sphere and Southwest Technical
Products, both using 6800-based systems. And
by this time I had already put out four issues of
Byte , the first magazine for the industry.

During 1976 the field expanded, with systems
from Imsai, Processor Tech, Polymorphics,
Wavemate, The Digital Group, OSI, Intelligent
Systems, M&R (Astral 2000), Apple, ECD,
TDL, Veras Systems, etc.

Of the 1975 firms, only SWTP is still around,
though I have seen few of their systems in stores
or ads in a long time, and interest in software
for their system seems to have disappeared. Ap-
ple has outperformed the 1976 group, with OSI
continuing to grow. The rest have either disap-
peared or virtually disappeared.

In 1977 we had more successful starts, with
Commodore, along with Heath, coming in ear-
ly, followed by Radio Shack in mid-year. Com-
modore threw away their lead and hundreds of
millions of dollars in sales by refusing to back
up their system with advertising and an aggres-
sive technical team. Heath tried to make a go of
it with only their 50 company-owned stores.
This, plus their refusal to go with the S-100 bus,
in my estimation, cost them tens of millions of
dollars in sales.

Radio Shack had a tough row to hoe at first.
Their store managers not only knew nothing
about computers, but most of them had little
understanding of audio or CB, so they were
afraid of this new invention and completely un-
equipped to cope with customers asking ques-
tions about ROMs and RAMs. They did have
several things going for them— a superb in-
struction book, written by David Lien, and
massive television and newspaper advertising.
They also benefited from the almost total con-
sumer invisibility of Commodore and Heath.

Approaching 1981, we’re looking into our
crystal ball to see what the microcomputer busi-
ness will look like in five more years. It’s almost
impossible to look with any clarity into the mid-
dle of next year, much less five years down the
pike. There are too many variables. If we as-
sume that there arc not going to be any more
quantum developments, such as the 8080 chip,
perhaps we can gain enough perspective to fig-

ure out where we can take advantage of what is
happening for our own benefit.

The first order of business in predicting the
future is to start with the market, presuming
that the industry will pursue the market, rather
than the reverse. The first computerists were
hobbyists. They had to be, because making a
computer from a kit, with pathetic instructions
and with a finished product that often had not
even worked in prototype, took considerable
skill to have any success. The early manufactur-
ers worked on the principle that hobbyists
would build the kits and figure out how to
make them work, thus performing the last ten
percent of the engineering for them. It turned
out that this system worked just fine, though it
severely frustrated several thousand hobbyists
in the process.

As the field matured, the early hobbyists
either got fed up with the expense and bum
equipment and dropped out, or became dealers
or manufacturers in the business. Many of
them are still around, taking advantage of the
things they learned during the first two years of
microcomputers.

With the advent of complete systems sales,
the electronic-type hobbyist decreased in im-
portance and was replaced by a new type of
hobbyist, one interested in using the computer
rather than building it. These new hobbyists
quickly became deeply involved in developing
utilities, writing programs, developing games
and generally finding out the capabilities of
their systems and expanding them.

There is still a good market for teenagers in-
terested in learning about computers. I think
this will continue, but I would expect it to be a
relatively limited market as compared to busi-
ness and educational applications. There may
be a few hundred thousand kids with $1000 to
spend on a hobby, but are there much more
than that? We’ll see.

The businessman sees the computer as a way
to save money and to get more done in less
time. But he is still wary of microcomput-
ers. . . and he should be. I am still awaiting arti-
cles written by businessmen who have invested
in microcomputer systems and found them to
be of distinct advantage to them. Most of the
letters I receive are to the contrary, expressing
frustration over delivery problems, over service
miseries and over the state of the software
available. I’ll be more convinced that the in-
dustry has an honest bargain for business when
I start getting articles by the dozens lauding sys-
tems and programs they are using.

Once we have systems that can actually be
used by business to save money and time, I
think they will sell in prodigious quantities.
Once we have systems that are clearly of value
to schools, I think we’ll be selling millions of
microcomputers.

Where do we stand with suppliers? Radio

Shack is out in front selling about three times
as many systems as Apple, the next firm in
line. That’s my guess. I’ve visited the Radio
Shack production facility and seen what they
are doing. Apple has not offered to let me see
theirs, so I don’t know what they are doing for
sure. But the sales figures that I have seen and
the polls of our readers indicate about a three
to one advantage for Radio Shack at present.
The new Apple III may make the Apple of
more interest for business applications, if they
are somehow able to come up with some soft-
ware support. In my discussions with Apple, I
have not been convinced that they are serious
about software — but then, neither is Radio
Shack.

Commodore has new management and is
starting to try to make up for lost time. They,
too, have some new systems to try and keep up
with the state of the art. It’s quite a race, with
Radio Shack fielding three new systems in Ju-
ly and one more promised for November,
bringing their coverage up to six current mod-
els.

Other firms, such as Atari, Mattel and Bal-
ly, are all substantial firms, but none of them
have shown any interest in more than minimal
software for their systems, so I will be sur-
prised if they do not waste a few million dol-
lars before dropping out. They are mainly
building extravagant toys to play games. I
can’t believe that this is a viable long-term
market. I think that these firms are so in-
volved with games that they got taken in by
the term “personal computer” and think that
there really is a market for personal toy com-
puter systems. Computer games will always be
popular on computers, but I don’t think that
many people (thousands maybe, but hundreds
of thousands?) are going to spend $1000 to
$2000 for a computer dedicated to games.

So we have several firms with good possibil-
ities for growth over the next few years. But
we also have a number of firms that seem to be
heading in the wrong direction, and none that
I have seen so far have any serious interest in
bettering their sales potential with the needed
software. I predict that one of the major firms
will suddenly discover the importance of soft-
ware and will quickly pass by all the others
when they put this discovery to use. Until that
happens, I see a battle taking place for a rela-
tively small market for microcomputers. I
don’t think the market will increase until there
is a large number of programs to support the
systems.

The Detroit Syndrome

The Japanese are getting ready to pounce,
and I suspect that their marketing plan is going

6 Microcomputing, October 1980

to be a lot more clever than those we have seen
from many of the American firms. The equip-
ment won’t be much better, but their advertis-
ing and marketing will be. Are they serious
about this? Matsushita, which markets here un-
der the Panasonic and Quasar names, is seri-
ous, and they think they are going to sell over
one million computers in 1981 in the U.S.
That’s a lot more than Radio Shack, Apple and
all the rest are figuring to sell.

Casio is thinking big, and with good reason.
They have done a fantastic job of taking over a
large share of the calculator market in the last
three years. 1 carry at least three Casio calcula-
tors, plus a Sharp Talking Clock, around with
me most of the time. I think Sharp will be here
soon with a computer, too. They are going hot
and heavy in Europe expanding their produc-
tion to where they can be very competitive.
Casio says they intend to be the biggest firm in
the business here in two years.

As more and more Japanese firms dig their
toes in at the starting line for the race across
America, I’m watching to see what our
American firms will do to counter this inva-
sion. So far this year we’ve seen entries from
Quasar, Panasonic and Casio, as well as from
NEC, with Sharp and Hitachi headed this way.
A reading of our trade literature makes it ap-
parent that these firms are very serious about
taking over and making microcomputers as
much of a Japanese preserve as are small cars,
stereo systems, television sets, CB radios, ama-
teur radios and most of the other high-technol-
ogy big -bucks consumer industries.

Surely our American microcomputer firms
are aware of what is happening and are prepar-
ing for the battle? This is not the case. In fact,
as I visit the American firms, I see a never-
never -land blindness to what is going on. Wish-
ful thinking and a euphoria resulting from suc-
cess have virtually wiped out reality.

How can you expect people who are making
fabulous salaries, working in lavish offices in
multi-building complexes— all generated in the
last year or two — surrounded by minions anx-
ious to please and fearful of sounding a disturb-
ing tone to have any perspective? Most of these
unfortunates have built up a dreamworld
around themselves and their accomplices. It
was in such a world that Processor Tech self-

destructed. This same protective buffer of
unreality helped Imsai to disintegrate. You can
be sure that not one of the new tycoons will
have the time to read this, much less think
seriously about it.

Thus, I see our American industry as being
very fragile, built on ever-increasing growth,
but virtually blind to what is going on outside
of the beautiful executive suites in Silicon
Valley as viewed through their tinted picture
windows facing on automatically watered grass
lawns. I see this as a scenario for disaster as the
hard-working and advertising-wise Japanese
start moving in.

At first, our industry will try to refuse to ac-
knowledge that the Japanese really exist or are
any serious threat. By the time they do begin to
see what is happening, it will be too late, and
they will be scrambling to see what, if anything,
can be salvaged from the ruin. We’ll see more
of the midnight back-door deals as the formerly
anointed back up rented trucks to grab as much
as they can from assembly lines before the
sheriff puts on the locks.

In addition to this number-one blindness,
which I expect the Japanese to exploit, there is
one other serious, and perhaps even terminal,
weakness in the American microcomputer in-
dustry. This is the same weakness that has
helped wipe out our car industry — pay scales.

Yes, I know all about the unresponsiveness
of the Detroit moguls to the desire for small
cars. But while it is unpopular to give the busi-
nessmen of Detroit credit for having any
brains, the fact is that these gentlemen were
well aware of the American need for economy
cars. But Detroit had a problem, an insoluble
problem: They could not compete against Ger-
many and Japan in building small cars because
the American auto workers were getting double
the average American wage, while the foreign
workers were making about the same wages as
Americans.

If Detroit could have started over and been
able to pay normal American wages, I would
not be driving an RX-7 Mazda and a Datsun
280Z, nor would I be considering a Rover 3500
as a new-car purchase. Japan moved in grad-
ually, keeping their costs down by paying nor-
mal wages to their people, keeping executive
overhead low and automating in every way
possible. I’m sure that our auto unions will
fight for their double the average American
wages until the last car company goes down the
tubes. We’ve seen this same mentality sinking
England for several years with no relief in sight.

I realized that American productivity has
been very low compared to other countries and
is dropping further behind, but I hadn’t real-
ized how much the wage scales forced on the
auto industry by the powerful unions had made
the industry unable to compete with foreign
auto makers, thus forcing the American firms
to keep making the larger gas guzzlers, which
foreign firms were not. Our firms made the on-
ly product they could sell and then backed this
up with their massive advertising system. Now
that is all falling apart.

How does this apply to the computer indus-
try? We have the same pattern for the Japanese
to exploit — excessive salaries, particularly in
Silicon Valley, where these astounding figures
are almost considered normal, an incredible

kiioboud

MICROCOMPUTING™

PUBLISHER/EDITOR

Wayne Green

ASSISTANT PUBLISHER/EDITOR

Jeff DeTray

ASSOCIATE PUBLISHER

Edward Ferman

MANAGING EDITOR

Dennis Brisson

ASST. MANAGING EDITOR

Susan Gross

COPY EDITOR

Eric Maloney

ADMINISTRATIVE ASSISTANTS

Suzy Clyne
Pat Graham
Nancy Noyd

ASSOCIATE EDITORS

Robert Baker
Ken Barbier
Frank Derfler, Jr.

Rod Hallen
Peter Stark
Sherm Wantz

DIRECTOR OF MANUFACTURING

Noel Self

ASST. DIRECTOR OF MANUFACTURING

Dion Owens

ART DIRECTOR

Diana Shonk

PRODUCTION DEPARTMENT
ART STAFF

William Anderson, Jr.

Steve Baldwin
Tedd Cluff
Linda Drew
Robert Drew
Bruce Hedin
Kenneth Jackson
Ross Kenyon
Clare McCarthy
Michael Murphy
Robert Sawyer
Patrice Scribner
Susan Symonds
John White

PHOTOGRAPHY

William Heydolph
Terrie Anderson
Reese Fowler

TYPESETTING
Barbara Latti
Sara Bedell
Linda Locke

EXECUTIVE VICE PRESIDENT

Sherry Smythe

CORPORATE CONTROLLER

Alan Thulander

EXECUTIVE ASSISTANT

Leatrice O’Neil

ACCOUNTING MANAGER

Knud Keller

CIRCULATION MANAGER

Debra Boudrieau

CIRCULATION

Barbara Block
Pauline Johnstone

BULK SALES MANAGER

Ginnie Boudrieau

ADVERTISING

603 - 924-7138

Kevin Rushalko, Mgr.

Marcia Stone
Hal Stephens

Microcomputing , October 1980 7

lack of automation in the factories and tremen-
dous overhead caused by armies of managers
and executives. These excesses, made possible
by the 300-400 percent growth per year of the
industry, are the seeds of its destruction. The
Japanese run a lean and mean ship, so they can
come in and stomp us with prices we can’t
match.

All those executives and opulence add sub-
stantially to the cost of our computers, adding
far more than the small import duties and ship-
ping costs from Japan. I predict that unless our
major firms get out of Silicon Valley and into
the low-rent districts and pay average Ameri-
can wages to the few people needed in much
more automated factories, we’ll see 90 percent
of the microcomputers coming from Japan
within five years.

Japan took over the ham equipment, stereo,
watch, calculator and radio markets. Now we
are seeing technology coming from Japan, in-
stead of from the U.S.

Despite this foreign influx, life goes on hap-
pily in Silicon Valley, with not even a ripple of
concern or reaction from our industry. Radio
Shack is in a lower-rent district, but they need
to pay attention to their corporate overhead
and lack of automation in their plants. They
also need some fast work on software support
of their products and advertising approach.
They do have the stores and a two-year head
start, so it would be a shame to see them blow it
now.

Japan already has some advantages over us
by virtue of their lower-cost memory and mi-
croprocessor chips. They pulled this off by out-
automating our chip firms, thus cutting down
the labor costs involved in making the chips.
They also have a substantial advantage over us
in employee efficiency, oddly enough, using
American know-how. You may have read some
of the spate of recent articles on how the
Japanese brought an American named Dem-
ming over to Japan and applied his ideas on a
national scale to improve their productivity and
attention to quality control.

The Japanese have well -developed Quality
Circles to attack every hint of a defect in the
quality of their products or service. They worry
about how many hours it takes for a computer
to be fixed for the customer, the quality of the
package it is sold in, the advertising and the
brochures. Every detail of business is relentless-
ly pursued for quality, and the result is superb
products, superb advertising and customer en-
thusiasm and confidence. I know when I buy a
Casio or Sony product that it is going to be first
class in every way and that I am not ever going
to have hassles. I wish I could say the same for
some of the American firms; my files are filling
with bitter customer complaints about their
quality and disregard of the customer.

It remains to be seen whether the microcom-
puter industry can learn from the Detroit deba-
cle and cut their corporate overhead, automate
and set up quality control for all phases of their
business before it is too late.

Yes, I am painting a grim picture, but my
facts are accurate and not exaggerated. I have
visited Apple, Atari, Commodore, Radio
Shack, Southwest Tech, Texas Instruments,
Ohio Scientific, Polymorphics, The Digital
Group, Wavemate, Imsai, Sphere, Mits, As-

tral, ECD, HP and others that don’t come im-
mediately to mind. I don’t think anyone else is
as intimately familiar with our industry. I’ve
been around right from the beginning, talking
with the top people in their plants and at shows.

UK Report

A letter from A. Zgorelec of Britain’s Per-
sonal Computer World magazine, by far the
largest of the UK microcomputing magazines
with over 100 pages of paid advertising, men-
tioned that a recent survey estimated that there
are about 60,000 microcomputers in that coun-
try. About half of those are PET systems, fol-
lowed by Apple in second place, Nascom (a
British computer, now in receivership) in third
place and Tandy (Radio Shack) in fourth, with
about 8000 systems sold. Tandy has only about
100 stores in UK, as opposed to over 400 stores
selling the PET. PET software is far more
available and in better quantity and quality.

I suspect that a quick infusion of Instant
Software might turn things around for Tandy
in UK, but obviously I’m prejudiced. This
would call for a change in company policy,
something that takes more than the loss of a
few million dollars to bring about. 80- Micro-
computing is well thought of by the Tandy
managers, but they are not allowed to recom-
mend the magazine to customers.

Clive Sinclair and his $200 single-board Z-80
computer are doing very well, with sales of over
8000 units in eight months and at least a 90-day
back-order situation currently. He’s making it
happen with full-page color ads in the leading
Sunday newspapers. This system was shown at
CES in Chicago in June, and the signs are that
they will be getting going in a serious way in the
U.S.

Other manufacturers of microcomputers in
UK are Transam, with their Tritan and Tuscan
systems, and Acorn Computer, with their
Atom and Research machines (strong in the
educational field).

Do Your Homework

It has come to my attention that a rather
large number of you readers have been goofing
off, not holding up your end of the system. I
will not tolerate laziness in a subscriber. When
you sign up for Microcomputing , you are doing
far more than sending in your crummy $25.
You are also expected to do your share of the
work.

For instance, as part of your responsibility,
you are expected to check out the new books
being offered by other publishers (we’ll take
care of reviewing ours) and write brief reviews,
pulling no punches about how good or how
lousy they are.

This also applies to software. If you purchase
a good piece of software, let us know. If you
find you’ve been screwed, level with us. We all
will benefit from the news, although Micro-
computing may lose an advertiser or two. We
even want to know your experiences with In-
stant Software.

While we are able to check out a lot of the
new hardware gadgets in our lab, it is impossi-
ble for us to do everything. There’s just too
much. So when you get a newly released prod-
uct, please send in a log of your experiences
with it so we can pass the information along to
the rest of the readers. We want to know how it
works, what problems you had and how re-
sponsive the manufacturer and dealer were.

You may work out some programming rou-
tines which would benefit others. If so, think of
Microcomputing as a way to pass along the in-
formation. You’ll reach the most people that
way ... by a wide margin. We’re all in this to-
gether, so the more we help each other, the bet-
ter off we’ll all be.

Send your reports to Software Reports, Mi-
crocomputing , Peterborough, NH 03458.

You are also expected to work hard to recruit
new subscribers, to put maximum pressure on
manufacturers and dealers to advertise, to loy-
ally buy advertised products, keeping your
readership of the magazine no secret in the pro-
cess, to respond enthusiastically to the reader
service card each month and do all you can to
help support the system of your choice.

If a friend has developed a gadget or worked
out a program of interest, get him to write it up
for Microcomputing. If you find a computer
store that does not have the magazine on dis-
play, let us know immediately so we can correct
this terrible state of affairs.

Send me newspaper or magazine articles
about microcomputers. I don’t want to miss
anything, but obviously I can’t read every pub-
lication there is, so I have to count on you.

Okay, now get busy.

Provide a “HELP” Command

It should not be news to programmers that
many of the users of computers are not experts.
This should be taken into consideration when
programs are written. All programs should
provide an explanation of how to use the pro-
gram by typing HELP.

Many times I find myself faced with a com-
puter program that does not respond to the
normal approaches. I really hate that. I don’t
like to be exposed, even to myself, for the dum-
my that I can be.

As we get more into business programs, we
will have to remember to make them simple to
use for someone who has walked up to the com-
puter for the first time. It is not necessary to
force experienced people to go through a lot of
explanatory stuff every time they want to use
the program, but a simple explanation should
be available on demand.

Programs submitted for publication and dis-
tribution by Instant Software will be trending
in this direction. So take note, programmers.

Conversions Requested

What is more frustrating than to turn the
page of a new issue of Microcomputing and
find just the program you need, only it has been
written for use on some other system!

8 Microcomputing, October 1980

If you are into programming, this will be a
hurdle, not a brick wall, and you’ll start keying
in the code and watching for any commands
you know will not perk through your own sys-
tem. Some systems conversions are more de-
manding than others, but, in general, there are
few programs that will not bend to an iron will.
Of course, when it comes to graphics, you’re
going to have to start pretty much from scratch
to generate them with your system. That’s
where the hard work comes in.

Once you’ve managed to adapt the program
to your system, why be stingy about it? Run off
a copy of the new program and send it in to Mi-
crocomputing for possible publication (paid) to
help others who are up against the problem but
don’t have the time (or smarts) to surmount it.
We’d appreciate a cassette copy, too. If you are
running a disk, send it in and we’ll get it back to
you later. This will enable us to check out your
version of the program in our lab and possibly
print out a clean listing for publication.

This will help readers with smaller-circula-
tion systems build up their program libraries.

Toes Stepped On

A recent “survey” in one of the newsprint
throwaways presented a rather biased report
with regard to Instant Software that deserves
comment.

The report observed that zero percent of In-
stant Software is written in-house. This is not
quite true. While ISI does not hire program-
mers to write programs, there are still quite a
number of programmers on the staff whose ef-
forts are added to many of the programs and
program packages that are released. The object
is to make every program as good as it can be
and an outstanding value. Thus, the staff often
adds routines to programs to enhance them, as
do associate editors, who work on contract.
The program authors are generally consulted as
to any changes in their works, so little of this
will come as a surprise to them.

Most of the programs published by ISI are,
indeed, volunteered by the programmers. But
there are some that are solicited from creditable
programmers, and there is some serious discus-
sion about getting some in-house programmers
to write a few needed types of programs that
have not yet been volunteered or have not been
received through solicitations.

The report stated that program evaluation
time at ISI was two to three months. About 75
percent of the rejections are made within the
first few days, and many programmers have re-
ceived this bad news within a week of sending in
their programs. Once a program gets by the
preliminary screening, it is admittedly a lengthy
process. But this is to the advantage of the pro-
grammer and to the customers. Programs that
appear to have promise are sent out to associate
editors for evaluation and possible improve-
ment. Only about 25 percent of the programs
are rejected after this more extensive evalua-
tion, so the preliminary check appears to be
valid and effective.

One of the major differences between ISI
and many (if not most) other software publish-
ers is the quality of the finished product. If a

program makes it through the lengthy process
at ISI, it is a good program. Customers and
dealers have found that they can depend upon
every ISI package to be top-notch and a very
good value. Yes, it does take longer to make
sure the quality is always good, but this is of
critical importance in the long run. Firms that
make quick decisions have a very poor quality
record.

The documentation for ISI is mostly done in-
house. Obviously, the better the material from
the author, the faster the program can be pro-
duced. ISI has a complete editorial staff to
write and edit the documentation, set it in type,
paste it up for printing, shoot the negatives for
printing, etc. Many of the instruction booklets
are even printed in the ISI pressroom. The
volume of orders has reached the point where
the in-house presses can’t handle them, so some
instruction booklets are printed by outside
printers. (The developing plans for a new ISI
building include a much larger printing depart-
ment.)

The biggest difference between software
publishers is in marketing. Small firms have
trouble getting the interest of most dealers,
since the bookkeeping involved soon becomes
prohibitive. Thus, a firm such as Instant Soft-
ware, with over a thousand released programs
from which to choose, greatly simplifies the
display and bookkeeping problems. Then,

Programmers will have
to be idiots to
bother to write programs
for sale if they
get little out of it.

too, ISI reps visit most stores once a month to
help them with their displays, to acquaint the
salespeople with the new releases, to pick up
slow-moving packages or to look into any
problems. It is this network of reps that has
enabled ISI to reach more stores — well over
400 stores worldwide at present— than any
other producer of software.

The royalties on ISI programs are normally
20 percent of the ISI gross. If the program is
sold by mail order, then the author receives 20
percent of the retail price. If a program sells to
a store at 33 percent discount, the author gets
20 percent of that receipt. About 90 percent of
the program sales at present are via dealers.
This percentage seems to be increasing as the
dealer network grows.

Articles about software publishing would
be of more value if they were better re-
searched. If a programmer just goes by the
meager facts presented in such a survey, he
could lose thousands of dollars in royalties by
being conned into going with a firm with fast
action and small distribution. And at least one
of the firms referenced in the report has been
fleecing programmers, despite the implied

seal of approval given by the publishing of the
survey.

Program Theft

I recently received through the mail a
Hayden software catalog, accompanied by a
letter that offered a ten-day free examination of
the programs. I’m reasonably honest, but I’m
not sure I could withstand that kind of tempta-
tion. I suspect that Hayden is so used to selling
books this way that they went right ahead and
used the same approach for their computer
programs.

While publishing books and computer pro-
grams have many similarities, there are some
important differences. A book is very difficult
and expensive to copy, so ten-day free offers
are a valid selling method. Computer pro-
grams, which are usually more expensive than
books, are so simple to copy that it is pathetic.
Free examination offers make no sense in this
field. Most of us are honest as long as you don’t
tempt us too far. But it is so simple to send
away for the whole catalog of Hayden pro-
grams, dump a copy on a cassette and then re-
turn them that I doubt that this sort of non-
sense will continue.

That brings me to the thinly disguised ser-
vices aimed right at program copiers. A chap
recently started up a “program library” service
that would lend computer programs for a frac-
tion of the regular sale price. Needless to say,
Instant Software, which was in his catalog, is
preparing a suit to stop this sort of theft.

I’ve had several letters telling me of clubs
that are allowing, or even encouraging, the
copying of programs. I hope that these clubs
are incorporated, because I’d hate to have to
sue every member of the club instead of just the
incorporated club itself. Where there is no cor-
poration, every member is liable for the actions
of the club. The usual practice is to sue all
members and then really go after those with
money.

It is only by pursuing these thefts of pro-
grams that the industry will be able to protect
the authors of programs. And it is only by pro-
tecting the ability to pay good royalties that we
shall have the programs that will allow micro-
computers to grow in their sales. To a great ex-
tent, much of the future of the whole industry
rests on the ability of software firms to support
the systems. Programmers will have to be idiots
to bother to write programs for sale if they get
little out of it.

While all this makes sense to everyone, peo-
ple continue to run off disk copies of dozens or
even hundreds of programs at the club, so why
pass it up? Well, I can’t speak for the other
firms in the business, but if just one person in
your club spills the beans to ISI, he stands a
good chance of making out rather well. We of-
fer a $10,000 reward for such information and
are very serious about it. We might well collect
quite a bit more than that in damages.

Give programmers a break and put a stop to
program theft wherever you see it being con-
doned. I think you’ll find very few computer
stores that will allow this anymore. There is just
far too much for them to lose.

Microcomputing, October 1980 9

«l Oskenes a surcharge ol $8 per

additional Oskefle Mil be added A surcharge of $25 wll be added for
software on CSSN formal DC 300X L cartridges Media charge lor 5440
is $100

Software /

with / Manual
Manual / Alone

No.16:

"lake a byte. 1

(ztCoAuruz C?/m /I flfylL

All Lifeboat programs require CP/M,
unless otherwise stated.

Software for most popular 8080/Z80
computer disk systems

Software /

with / Manual
Manual ' Alone

□ CP/M* FLOPPY DISK OPERATING SYS-
TEM— Digital Research s operating system
configured for many popular micro-computers
and disk systems:

System Version Price

, Apple II* 2.x. .. .350/25 0

SoftCard* with Z80
Microsoft BASIC version 5
with high resolution
graphics

North Star Single Density ...1.4... .145/25 ®
North Star Double Density .1.4 — 145/25
North Star Single Density . . 2.x — 170/25
North Star Double/Quad . . .2.x . 170/25

Durango F-85 2.x ... 170/25

(COM Micro-Disk 2411 1.4. 145/25

iCOM 3712 1.4. . .170/25®*

iCOM 3812 1.4 . . . .170/25*

Mils 3202/Altair 8800 1.4... 145/25

Heath H8 + Hi 7 1.4 . 145/25®

Heath H89 1.4. .. 145/25®

Heath H89 by Magnolia ..1.4... 250/25 O
Heath H89 by Magnolia ... 2.x . 300/25 O

Onyx C8001 2.x . 300/25 O

Ohio Scientific C3 2.x . 200/25

TRS-80 Model I 1.4... .145/25 ®

TRS-80 Model II

TRS-80 Model II 4- Corvus

•are /
with / M
null/ Al

□ SMAL/80 Structured Macro Assembler
® Language— Package of powerful general
purpose text macro processor and SMAL
structured language compiler. SMAL is an as-

□ FORTRAN-80 -ANSI 66 (except for COM-
© PLEX) plus many extensions. Includes reiocat-
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manager. Also includes MACRO-80 (see
below) $425/525

□ COBOL-80 — Level 1 ANSI ’74 standard
© COBOL plus most of Level 2. Full sequential.
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file names. STRING. UNSTRING, COMPUTE.
VARYING/UNTIL, EXTEND. CALL, COPY.
SEARCH. 3-dimensional arrays, compound
and abbreviated conditions, nested IF. Powerful
interactive screen-handling extensions. In-
cludes compatible assembler, linking loader,
and relocatable library manager as described
under MACRO-80 $700/$25

□ MACRO-80 — 8080/Z80 Macro Assembler.
© Intel and Zilog mnemonics supported. Relocat-
® able linkable output. Loader, Library Manager

and Cross Reference List utilities
included $149/515

□ muSIMP/muMATH-muSIMP is a high level
© programming language suitable for symbolic

.and semi-numerical processing. Implemented

?fL™kl^Janguage .. w i th JJ!' 'I^I N ^^^j|\|^J^using a fast and efficient interpreter requiring

»/ ?

LOOP-REPEAT-WHILE. DO-END, BEGIN ,
END constructs $75/515

PHOENIX SOFTWARE ASSOCIATES

□ PASM* — Z80 macro assembler, Intel/TDL

mnemonics. Generates Intel hex format or re-
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'format or PSA Relocatable Binary Module for-
mat. Supports text insertion, conditional
branching within macros, recursive macro calls
and parameter passing $129/525

□ EDIT— Character oriented text file editor. In-
® eludes macro definition capabilities. Handles

insertion, deletion, searching, block move, etc.
for files of any length. Does not require a
CRT. $129/525

□ PUNK* — Two pass disk-to-disk linkage edi-
® tor/loader which can produce re-entrant,

ROMable code. Can link programs that are
larger than available memory for execution
targeted on another machine. Full library
capabilities. Input can be PSA Relocatable Bi-
nary Module, TDL Object Module or Microsoft
REL files. Output can be a COM file. Intel hex
file. TDL Object Module or PSA Relocatable
file $129/525

□ BUG* and /xBUG* — Z80 interactive machine
® level debut

« 1 70/25 w ,evei uBuugging tools for program develop-

l I [a . A rnent. BUG has full symbolic trace and interac-

c.x — Mli/^tive assembly (mnemonics compatible with

Processor Technology ^ S M) ' 5yn7m!c bre^

Hel,os 11 1 4 1 45/25 traps while tracing (even through ROM!). m BUG

is a subset of BUG and is used in memory
limited situations $129/525

Cromemco System 3 —

..1.4..

145/25

Intel MDS Single Density .

.1.4..

145/25

Intel MDS Single Density .

. . 2.x . .

170/25

Micropolis Mod 1

. . 1.4. .

145/25®

Micropolis Mod II

. . 1.4

145/25®

The following configurations are scheduled for
release soon:

North Star Double/Quad

+ Corvus

,2.x. .

250/25

North Star Horizon HD-1 . .

. 2.x . .

250/25

Ohio Scientific C3-C

,2.x. .

250/25

Micropolis Mod II

Mostek MDX STD

,2.x . .

200/25

Bus System

. 2.x . .

350/25 **

iCOM 3812

,2.x . .

225/25 *

iCOM 451 1 /Pert ec D3000 .

. 2.x . .

375/25 *+

Software consists of the operating system, text
editor, assembler, debugger and other utilities
for file management and system maintenance.
Complete set of Digital Research's documen-
tation and additional implementation notes in-
cluded. Systems marked * and ** include firm-
ware on 2708 and 2716. Systems marked + in-
clude 5440 media charge. Systems marked
® require the special ® versions of soft-
ware in this catalog. Systems marked ® have
minor variants available to suit console inter-
face of system. Call or write for full list of op-
tions. O includes hardware addition to allow our
standard versions of software to run under it.

□ Z80 DEVELOPMENT PACKAGE -Consists

® of: (1) disk file line editor, with global inter and
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(3) linking loader producing absolute Intel hex
disk file $95/520

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when ordered with Z80 Development
Package $50/510

AVOCET SYSTEMS

□ X ASM-68— Non-macro cross-assembler with
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MCS-6500 series mnemonics $200/525

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UPI-41 families $200/525

□ XASM-18— As XASM-68 for RCA 1802
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DIGITAL RESEARCH

□ MP/M — Installed for single density MDS-800.

Multi-processing derivative of the CP/M op-
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□ MAC-8080— Macro assembler. Full Intel
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IRP, REPT, TITLE, PAGE, and MACUB. Pro-
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for use by SID and ZSID (see below) $1 20/51 5

□ SID-8080 — Symbolic debugger. Full trace,
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Has backtrace and histogram utilities. When
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□ ZSID-Z80— Symbolic debugger with all fea-

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®

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only 7K bytes of machine code muMATH i:
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tegration of definite and indefinite integrals.
Requires 40K CP/M $250/520

□ muLISP-79 — Microcomputer implementation
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of memory yet includes 83 LISP functions. Has
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□ XMACRO-86 — 8086 cross assembler. All

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available $275/525

□ EDIT-80 — Very fast random access text editor
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intra-line commands supported. File compare
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INPORT. OUTPORT and untyped files for arbi-
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CDOS $175/520

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support library. The package includes compiler,
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CP/M $395/525

□ RASCAL/MT — Subset of standard PASCAL.
® Generates ROMable 8080 machine code.
® Symbolic debugger included. Supports inter-
rupt procedures, CP/M file I/O and assembly
language interface. Real variables can be BCD,
software floating point, or AMD 9511 hardware
floating point. Includes strings enumerations
and record data types. Manual explains BASIC
to PASCAL conversion. Requires 32K . $250/
S30

□ APL/V80 — Concise and powerful language for
© application software development. Complex
® programming problems are reduced to simple

® teaching structured programming techniques. \ ,i) expressions in APL. Features include up to 27K
Manual includes full source listings .5105/550 N active workspace, shared variables, arrays of
c BDS C COMPILER- Supports most features 1 ^ up to 8 dimensions, disk workspace and copy

rr . . , vT . * lihrorw Tho ewefom alcn ci innnrrc qiiviI-

® of language, including Structures. Arrays.

© Pointers, recursive function evaluation, over-
lays. Includes linking loader, library manager,
and library containing general purpose, file I/O.
and floating point functions. Lacks initializers,
statics, floats and longs. Documentation in-
cludes "The C PROGRAMMING LANGUAGE"

by Kernighan and Ritchie $145/525

□ WHITESMITHS C COMPILER -The ultimate
© in systems software tools. Produces faster
® code than a pseudo-code Pascal with more
extensive facilities. Conforms to the full UNIX*

Version 7 C language, described by Kernighan
and Ritchie, and makes available over 75 func-
tions for performing I/O, string manipulation
and storage allocation. Linkable to Microsoft
REL files. Requires 60K CP/M $630/530

object library. The system also supports auxil-
iary processors for interfacing I/O ports. Re-
quires 48K CP/M and serial APL printing termi-
nal or CRT 5500/530

□ ALGOL-60 — Powerful block-structured lan-
® guage compiler featuring economical run-time

dynamic allocation of memory. Very compact
(24K total RAM) system implementing almost
all Algol 60 report features plus many powerful
extensions including string handling direct disk
address I/O etc $199/520

□ CBASIC-2 Disk Extended BASIC- Non-
® interactive BASIC with pseudo-code compiler

and run-time interpreter. Supports full file con-
trol, chaining, integer and extended precision
variables, etc $120/515

MICROSOFT

n BASIC-80- Disk Extended BASIC, ANSI
© compatible with long variable names,

® WHILE/WEND, chaining, variable length file
records $325/525

□ DISTEL— Disk based disassembler to Intel

8080 or TDL/Xitan Z80 source code, listing and
cross reference files, Intel or TDL/Xitan pseudo
ops optional. Runs on 8080 $65/510

□ DISILOG-As DISTEL to Zilog/Mostek

® mnemonic files $65/510

®

Lifeboat Associates, 1651 Third Avenue. N.Y., N.Y. 10028 (212) 860-0300 Telex: 220501

□ BASIC COMPILER — Language compatible
© with BASIC-80 and 3-10 times faster execution.
® Produces standard Microsoft relocatable bi-
nary output. Includes MACRO-80. Also linkable
to FORTRAN-80 or COBOL-80 code
modules 5350/525

MICRO FOCUS

□ STANDARD CIS COBOL -ANSI 74 COBOL

© standard compiler fully validated by U.S. Navy
tests to ANSI level 1 . Supports many features to
level 2 including dynamic loading of COBOL
modules and a full ISAM file facility. Also, pro-
gram segmentation, interactive debug and
powerful interactive extensions to support pro-
tected and unprotected CRT screen formatting
from COBOL programs used with any dumb
terminal 5850/550

Lifeboat Associates GmbH, Aegeristr. 35. 6340 Baar Telefon 042/31 2931

Software

Manual

□ FORMS 2 — CRT screen editor. Output is
© COBOL data descriptions for copying into CIS
COBOL programs. Automatically creates a
query and update program of indexed files
using CRT protected and unprotected sdreen
formats. No programming experience needed.
Output program directly compiled by STAN-
DARD CIS COBOL $200/520

EIDOS SYSTEMS

□ KISS — Keyed Index Sequential Search. Offers

© complete Multi-Keyed Index Sequential and Di-
rect Access file management. Includes built-in
utility functions for 16 or 32 bit arithmetic,
string/integer conversion and string compare.
Delivered as a relocatable linkable module in
Microsoft format for use with FORTRAN-80 or
COBOL-80, etc $335/523

□ KBASIC- Microsoft Disk Extended BASIC
© version 4.51 integrated by implementation of

nine additional commands in language. Pack-
age includes KISS. REL as described above,

and a sample mail list program $585/545

To licensed users of Microsoft BASIC-80
(MBASIC) $435/545

□ X YB ASIC Interactive Process Control
BASIC— Full disk BASIC features plus unique
commands to handle byte rotate and shift and
to test and set bits. Available in several ver-

sions:

Integer ROM squared $350/525

Integer CP/M 5350/525

Extended ROM squared $450/525

Extended CP/M $450/525

Extended Disk CP/M $550/525

Integer CP/M Run Time Compiler 5350/525
Extended CP/M Run Time Compiler$450/$25

□ RECLAIM — A utility to validate media under

CP/M. Program tests a diskette or hard disk
surface for errors, reserving the imperfections
in invisible fi(es, and permitting continued
usage of the remainder. Essential for any hard
disk. Requires CP/M version 2 $80/55

□ BASIC UTILITY DISK -Consists of: (1)

® CRUNCH-14— Compacting utility to reduce

the size and increase the speed of programs in
Microsoft BASIC 4.51, BASlC-80 and TRS-80
BASIC. (2) DPFUN — Double precision subrou-
tines for computing nineteen transcendental
functions including square root, natural log, log
base 10, sine, arc sine, hyperbolic sine, hyper-
bolic arc sine, etc. Furnished in source on dis-
kette and documentation $50/535

□ STRING/80 — Character string handling plus
routines for direct CP/M BDOS calls from
FORTRAN and other compatible Microsoft lan-
guages. The utility library contains routines that
enable programs to chain to a COM file, retrieve
command line parameters and search file direc-
tories with full wild card facilities. Supplied as
linkable modules in Microsoft format. 595/520

□ STRING/80 source code available

separately— 5295/NA

□ THE STRING BIT- FORTRAN character

® string handling. Routines to find, fill, pack,

move, separate, concatenate and compare
character strings. This package completely
eliminates the problems associated with
character string handling in FORTRAN.
Supplied with source 565/515

□ VSORT — Versatile sort/merge system for fixed

® length records with fixed or variable length

fields. VSORT can be used as a stand-alone
package or loaded and called as a subroutine
from CBASIC-2. When used as a subroutine,
VSORT maximizes the use of buffer space by
saving the TPA on disk and restoring it on com-
pletion of sorting. Records may be up to 255
bytes long with a maximum of 5 fields. Upper/
lower case translation and numeric fields
supported $175/520

□ CPM/374X— Has full range of functions to cre-

ate or re-name an IBM 3741 volume, display
directory information and edit the data set con-
tents. Provides full file transfer facilities be-
tween 3741 volume data sets and CP/M
files $195/510

□ MASTER TAX — Professional tax preparation
© program. Prepares schedules A, B, C, D, E, F,
t G. R/RP, SE, TC, ES and forms 2106, 2119,

2210, 3468. 3903. 2441, 4625, 4726. 4797,
4972, 5695 and 6521 . Printing can be on readily
available, pre-printed continuous forms, on
overlays, or on computer generated, IRS ap-
proved forms. Maintains client history files and
is interactive with CPAids GENERAL LEDGER

II (see below) 5995/530

n STANDARD TAX -As above for schedules A.
t B, C, D, E, G, R/RP, SE. TC and forms 2106 and
2441. Also, does not maintain client history
files $495/530

□ GENERAL LEDGER II- Designed for CPAs,
t Stores complete 12 month detailed history of

transactions. Generates financial statements,
depreciation, loan amortizations, journals, trial
balances, statements of changes in financial
position, and compilation letters. Includes
payroll system with automatic posting to gen-
eral ledger. Prints payroll register, W2's and
payroll checks $450/530

Software /
with /
Manual/

Manual

Alone

□ T/M AKER — Powerful new tool for preparing

management reports with tabular data. Makes
financial modeling projects easy. Do you want a
weekly profitability report? Set up the table and
compute. Just change the sales figures for next
week and compute. You have a new report!
T/MAKER includes a full screen editor for
setting up tables which pages left, right, up
and down. Compute includes standard arith-
metic, percents, exponents, common tran-
scendental functions, averages, maxima,
minima, projections, etc. Requires 48K CP/M
and CBASIC-2 $275/$25

□ BSTAM — Utility to link one computer to another

<8> also equipped with BSTAM. Allows file transfers

at full data speed (no conversion to hex), with
CRC block control check for very reliable error
detection and automatic retry. We use it! It's
great! Full wildcard expansion to send *. COM,
etc. 9600 baud with wire. 300 baud with phone
connection. Both ends need one. Standard and
® versions can talk to one another. .$150/$10

□ WHATSIT?* — Interactive data-base system
using associative tags to retrieve information by
subject. Hashing and random access used for
fast response. Requires CBASIC-2 .$175/525

□ SELECTOR III-C2 — Data Base Processor to

t create and maintain multi-key data bases.

® Prints formatted sorted reports with numerical

summaries or mailing labels. Comes with sam-
ple applications, including Sales Activity, Inven-
tory, Payables, Receivables, Check Register,
and Client/Patient Appointments, etc. Requires
CBASIC-2. Supplied in source $295/520

□ GLECTOR — General Ledger option to

SELECTOR III-C2. Interactive system provides
for customized COA. Unique chart of transac-
tion types insure proper double entry book-
keeping. Generates balance sheets, P&L
statements and journals. Two year record al-
lows for statement of changes in financial posi-
tion report. Supplied in source. Requires
SELECTOR III-C2. CBASIC-2 and 56K
system $350/525

□ CBS — Configurable Business System is a

comprehensive set of programs for defining
custom data files and application systems with-
out using a programming language such as
BASIC, FORTRAN, etc. Multiple key fields for
each data file are supported. Set-up program
customizes system to user's CRT and printer.
Provides fast and easy interactive data entry
and retrieval with transaction processing
Report generator program does complex calcu-
lations with stored and derived data, record
selection with multiple criteria, and custom for-
mats. Sample inventory and mailing list sys-
tems included. No support language
required $295/$40

MICRO DATA BASE SYSTEMS

□ HDBS — Hierarchical Data Base System.
CODAS YL oriented with FILEs. SETs. REC-
ORDS and ITEMs which are all user defined.
ADD, DELETE, UPDATE. SEARCH, and
TRAVERSE commands supported. SET order-
ing is sorted, FIFO, LIFO, next or prior. One to
many set relationship supported. Read/write
protection at the FILE level. Supports FILEs
which extend over multiple floppy or hard disk
devices.

□ WORD-STAR — Menu driven visual word pro-
© cessing system for use with standard terminals.

Text formatting performed on screen. Facilities
for text paginate, page number, justify, center
and underscore. User can print one document
while simultaneously editing a second. Edit
facilities include global search and replace.
Read/Write to other text files, block move, etc.
Requires CRT terminal with addressable cursor
positioning $445/ $40

□ WORD-STAR-MAIL-MERGE- As above with
© option for production mailing of personalized

documents with mail lists from DAT AST AR or
NAD $575/$40

□ WORD-STAR Customization Notes— For

sophisticated users who do not have one of the
many standard terminal or printer configura-
tions in the distribution version of WORD-
STAR $NA/$95

□ WORD-MASTER Text Editor— In one mode

© has superset of CP/M’s ED commands includ-
ing global searching and replacing, forwards
and backwards in file in video mode, provides
full screen editor for users with serial address-
able-cursor terminal $145/$25

□ TEXTWRITER III— Text formatter to justify and
® paginate letters and other documents. Special
features include insertion of text during execu-
tion from other disk files or console, permitting
recipe documents to be created from linked
fragments on other files. Has facilities for sorted
index, table of contents and footnote insertions.
Ideal for contracts, manuals, etc. Now compati-
ble with Electric Pencil* and Word-Star pre-
pared files S125/S20

PEACHTREE SOFTWARE

□ General accounting software for small busi-
© nesses. Each product can be used alone or with
t automatic posting to the general ledger.
Supplied in source for Microsoft BASIC 4.51.

GENERAL LEDGER $530/540

ACCOUNTS PAYABLE $530/540

ACCOUNTS RECEIVABLE $530/$40

PAYROLL $530/$40

INVENTORY 5660/S40

ALSO:

MAILING ADDRESS $530/540

PROPERTY MANAGEMENT $925/$40

GRAHAM-DORIAN SOFTWARE
SYSTEMS

□ Comprehensive accounting software written in
© CBASIC-2 and supplied in source code. Each
® software package can be used as a stand-alone
t system or integrated with the General Ledger
for automatic posting to ledger accounts. Re-
quires CBASIC-2.

GENERAL LEDGER $805/540

ACCOUNTS PAYABLE $805/$40

ACCOUNTS RECEIVABLE $805/$40

INVENTORY SYSTEM $555/$40

JOB COSTING $805/540

APARTMENT MANAGEMENT . . $805/$40
CASH REGISTER $805/540

G MDBS — Micro Data Base System. Full network
data base with all features of HDBS plus multi-

□ POSTMASTER — A comprehensive package
level read/write protection for FILE, SET, REC- ■ j ® ,or mail Bat maintenance that is completely
ORD and ITEM. Explicit representation of one N^^menu driven - Features include keyed record
toone. oneto manv. manvtomanv. andmanvto for extraction and label production. A form letter

program is included which provides neat letters
on single sheet or continuous forms. Includes

to one, one to many, many to many, and many to fo*
one SET relationships. Supports multiple
owner and multiple record types within SETs. D J

HDBS files are fully compatible. K*^ NAD file translator. Requires CBASIC-2

□ HDBS-Z80 version $250/$40** $150/520

□ MDBS-Z80 version $750/$40**

8080 version available at $75 extra.

When ordering, specify one of the language
interfaces listed below. Additional language in-
terfaces available at time of purchase for $100
or $125 if purchased later.

**The single manual covering HDBS and
MDBS when purchased alone comes without
specific language interface manual. Manuals
are available for the following Microsoft lan-
guages:

1) MBASIC 4.51. 2) BASIC-80 5.0. 3) Compiled
BASIC or FORTRAN-80, 4) COBOL-80. 5)
MACRO-80 SNA/ $10

MICROPRO

□ SUPER-SORT I — Sort, merge, extract utility as
© absolute executable program or linkable mod-
ule in Microsoft format. Sorts fixed or vanable
records with data in binary, BCD. Packed Deci-
mal, EBCDIC, ASCII, floating & fixed point, ex-
ponential, field justified, etc. Even variable

number of fields per record! S225/S25

□ SUPER-SORT II— Above available as abso-

© lute program only S175/S25

□ SUPER-SORT III- As II without SELECT/

© EXCLUDE $125/525

□ DATASTAR — Professional forms control entry
© and display system for key-to-disk data cap-
ture. Menu driven with built-in learning aids.
Input field verification by length, mask, attribute
(i.e. uppercase, lower case, numeric, auto-dup.
etc.). Built-in arithmetic capabilities using keyed
data, constant and derived values. Visual feed-
back for ease of forms design. Files compatible
with CP/M-MP/M supported languages. Re-
quires 32K CP/M $350/$35

STRUCTURED SYSTEMS GROUP

□ Complete interactive accounting software for
t business. Each product can be used stand-
alone or with automatic posting to the general
ledger. Each product is thoroughly tested and
very well documented. Each product requires
CBASIC-2.

GENERAL LEDGER S820/S40

ACCOUNTS RECEIVABLE $820/$40

ACCOUNTS PAYABLE $820/$40

PAYROLL $820/540

INVENTORY CONTROL $820/540

NEWiNEWSLETTI
FROM LIFEBOAT

• Latest Version
Numbers List
of Software

• Update on
CP/M Users Group

• The Great ZOSO Speaks
Out from Behind the Scenes

$18 ppd. for 12 issues (U.S.. Canada.
Mexico). Elsewhere $ 40 .

Send Check to "Lifelines," 1651 Third Avenue,
New York, N.Y. 10028 or use your VISA or
Mastercharge — call (212) 722-1700

Copyright © 1980 Lifeboat Associates. No por-
tion of this advertisement may be reproduced
without prior permission.

□ ANALYST— Customized data entry and report-

t ing system. User specifies up to 75 data items

per record. Interactive data entry, retrieval,
and update facility makes information
management easy. Sophisticated report
generator provides customized reports using
selected records with multiple level break-
points for summarization. Requires a disk sort
utility such as QSORT, SUPER-SORT or
VSORT and CBASIC-2 $250/515

□ LETTERIGHT— Program to create, edit and

type letters or other documents. Has facilities to
enter, display, delete and move text, with good
video screen presentation. Designed to inte-
grate with NAD for form letter mailings. Re-
quires CBASIC-2 $200/525

□ NAD Name and Address selection system —

Interactive mail list creation and maintenance
program with output as full reports with refer-
ence data or restricted information for mail
labels. T ransfer system for extraction and trans-
fer of selected records to create new files. Re-
quires CBASIC-2 $100/$20

□ QSORT— Fast sort/merge program for files
with fixed record length, variable field length
information. Up to five ascending or descend-
ing keys. Full back-up of input files created

$1 00/$20

★ ★★★★★★

CONDIMENTS

★ ★★★★★★

□ HEAD CLEANING DISKETTE- Cleans the
drive Read/Write head in 30 seconds. Diskette
absorbs loose oxide particles, fingerprints, and
other foreign particles that might hinder the per-
formance of the drive head. Lasts at least 3
months with daily use. Specify 5" or 8' .

Single sided $20 each/$55 for 3

Double sided $25 each/$65 for 3

□ FLIP°Y DISK KIT— Template and instructions

to modify single sided 5V*" diskettes for use of
second side in single sided drives $12.50

□ FLOPPY SAVER — Protection for center holes
for 5" and 8" floppy disks. Only 1 needed per
diskette. Kit contains centering post, pressure
tool and tough 7 mil mylar reinforcing rings for

25 diskettes.

5", Kit $14.95

5', Rings only $7.95

a , Kit $16.95

8". Rings only $8.95

□ PASCAL USER MANUAL AND REPORT-

By Jensen and Wirth. The standard textbook on
the language. Recommended for use by
Pascal/Z, Pascal/M and Pascal/MT users $12

□ THE C PROGRAMMING LANGUAGE-By

Kernighan and Ritchie. The standard textbook
on the language. Recommended for use by
BDS C, tiny C, and Whitesmiths C users . $12

□ STRUCTURED MICROPROCESSOR PRO-

GRAMMING -By the authors of SMAL/80.
Covers structured programming, the 8080/
8085 instruction set and the SMAL/80 lan-
guage $20

□ ACCOUNTS PAYABLE & ACCOUNTS

RECEIVABLE — C BASIC — By Osborne/
McGraw-Hill $20

□ GENERAL LEDGER - CB ASIC - By

Osborne/McGraw-Hill $20

□ PAYROLL WITH COST ACCOUNTING-

CBASIC- by Osborne/McGraw-Hill $20

□ LIFEBOAT DISK COPYING SERVICE-

Transfer data or programs from one media for-
mat to another at a moderate cost from $25

★ ★★★★★★
Hearty Appetite.

i i i i ^

*CP/M and MP/M are trademarks of Digital Re-
search.

Z80 is a trademark of Zilog. Inc.

UNIX is a trademark of Bell Laboratories.
WHATSIT? is a trademark of Computer Head-
ware.

Electric Pencil is a trademark of Michael
Shrayer Software.

TRS-80 is a trademark of Tandy Corp.
Pascal/M is a trademark of Sorcim.

SoftCard is a trademark of Microsoft.

Apple is a trademark of Apple Computer.
PASM, PLINK, BUG and/x BUG are trademarks
of Phoenix Software Associates Ltd.

CPAids is a trademark of Computer Tax Ser-
vice, Inc.

t Recommended system configuration consists
of 48K CP/M, 2 full size disk drives, 24 x 80 CRT
and 132 column printer.

® Modified version available for use with CP/M as
implemented on Heath and TRS-80 Model I
computers.

© User license agreement for this product must
be signed and returned to Lifeboat Associates
before shipment may be made.

© This product Includes/eXcludes the language
® manual recommended in Condiments.

© Serial number of CP/M system must be
supplied with orders.

® Requires Z80 CPU.

Ordering Information

MEDIA FORMAT ORDERING CODES
When ordering, please specify format code.

LIFEBOAT ASSOCIATES MEDIA FORMATS LIST

Diskette, cartridge disk and cartridge tape format codes to be
specified when ordering software for listed computer or disk
systems. All software products have specific requirements in
terms of hardware or software support, such as MPU type,
memory size, support operating system or language.

Computer tyetem Format Coda

AKair 8800 Disk See MITS 3200

Altos AT

Apple + SoftCard 13 Sector RG

Apple + SoftCard 16 Sector RR

BASF System 7100 RD

Blackhawk Single Density Q3

Btackhawk Micropolis Mod II ... Q2

CDS Versatile 3B Q1

CDS Versatile 4 Q2

COM PAL-80 Q2

Cromemco System 3 A1*

Cromemco Z2D R6

CSSN BACKUP (tape) T1 #

Delta AT

Dlgl-Log Microterm II RD

Digital Microsystems AT

Discus See Morrow Discus

Durango F-85 RL

Dynabyte DB8/2 Rl

Dynabyte DB8/4 AT

Exidy Sorcerer + Lifeboat CP/M .02

Exidy Sorcerer + Exidy CP/M .04

Heath H8 + H17/H27 P4

Heath H89 + Lifeboat CP/M P4

Heath H89 * Magnolia CP/M P7

Helios II See Processor Technology

Horizon See North Star

iCOM 241 1 Micro Floppy R3

iCOM 3712 A1

iCOM 3812 AT

iCOM 451 1 5440 Cartndge

CP/M 1.4 01#

ICOM 4511 5440 Cartndge
CP/M 2.2 D2#

Prices F.O.B. New York.
Shipping, handling and C.O.D.
charges extra.

Manual cost applicable against
price of subsequent software
purchase.

The sale of each proprietary
software package conveys a
license for use on one
system only.

Computer system Format Code

IMS 5000 RA

IMS 8000 AT

IMSAI VDP-40 R4**

IMSAI VDP-42 R4”

IMSAI VDP-44 R5‘*

IMSAI VDP-80 AT*

Intecolor See ISC Intecblor

Intel MDS Single Density A1

Intertec SuperBrain DOS 0.1 R7

Intertec SuperBrain DOS 0.5-2.X .RJ

Intertec SuperBrain DOS 3.X RK

ISC Intecolor 8063/8360/8963 A1

Kontron PSI-80 RF

Meca 5V P6

Micromation

(Except TRS-80 below) AT

Micropolis Mod I Q1

Micropolis Mod II Q2

MITS 3200/3202 B1

Morrow Discus AT

Mostek A1

MSD5W RC

North Star Single Density Pi

North Star Double/Quad P2

Nytac Single Density Q3

Nylac Micropolis Mod II Q2

Ohio Scientific C3 A3

Onyx C8001 T2#

Penec PCC 2000 AT

Processor Technology Helios II . ,B2

Quay 500 RO

Quay 520 RP

RAIR Single Density R9

RAIR Double Density RE

* Single-Side Single-Density disks
are supplied for use with Double-
Density and Double-Side 8 soft
sector format systems.

** IMSAI formats are single density
with directory offset ol zero.

# A media surcharge of $25 for or-
ders on tape formats T 1 and T2 and
of $100 for orders on disk formats
Di and 02 will be added.

The list of available formats is sub-
ject to change without notice. In
case of uncertainty, call to confirm
the format code for any particular
equipment.

Computer system Format Code

Research Machines 8 A1

Research Machines 5V«' RH

REX Q3

Sanco 7000 5%' RQ

SD Systems 8 AT

SO Systems 5V4" R3

Sorcerer See Exidy Sorcerer

Spacebyte .A1

SuperBrain See Intertec

Tarbell AT

TEI5V« R3

TEir AT

Thtnkertoys See Morrow Discus

TRS-80 Model 1 8W R2

TRS-80 Model I + FEC Freedom RN
TRS-80 Model 1 4 Micromation ,A4*
TRS-80 Model I + Omikron 5W RM
TRS-80 Model I + Omikron 8" A1
TRS-80 Model I + Shuffleboard 8 A1

TRS-80 Model II AT

VDP-40/42/44/80 . . See IMSAI

Vector MZ Q2

Versatile See CDS Versatile

Vista V80 5W Single Density P5
Vista V200 5V«" Double Density . P6
Zenith Z89 + Lifeboat CP/M P4
Zenith Z89 + Magnolia CP/M P7

lifeboat Associates

The Software Supermarket is a trademark of Lifeboat Associates

Robert W. Baker

PET-POURR1

Proganal

I recently received an interesting and impres-
sive utility program for the 8K PET from Ben-
son Greene, 210 Fifth Ave., New York, NY
10010. The program is called Proganal and
provides two separate functions: It can list a
BASIC program with special formatting and
cursor character conversion and can generate a
detailed analysis of the actual content and
structure of the program. This program was ex-
tremely interesting to me, since it follows the
line of several programs I’ve worked on in the
past.

The program listings produced by Proganal
are formatted with page indications for fold-
ing, headings and binding instructions. This is
convenient, since the output is designed for
five-inch-wide roll paper. The page indications
make it easy to fold the listings into a usable
form. A separating line after any breaks in the
logic sequence of the program is also provided.

All PET graphics and cursor controls are
printed in a form that prevents misinterpreta-
tion, regardless of any printer limitations. All
hidden, secret lines that contain delete graphics
are printed in full, and any shifted blanks are
identified.

The detailed program analysis includes a
wealth of information for the subject BASIC
program. It shows all program variables,
sorted by name and type, with all line-number
references indicated. All BASIC commands,
along with their line-number references, are
listed. Any functions or operators are tallied,
showing the total number of times each is used
in the program. Each branch instruction, along
with every reference line for the branch
“target” line, is listed.

At the end of the analysis, a summary report
is printed showing the number of program lines
and the range of line numbers used, the total
number of BASIC instructions, the total num-
ber of variable references, the number of dif-
ferent variable names, the number of branches,
the number of logic decisions, a relative com-
plexity figure (shown as %) and the time to pro-
cess the program file. The analysis output is
also formatted and paged in the same format as
that used for generating the program listing.

Proganal can handle programs with up to
300 distinct, separate line-number references
for each letter of the alphabet, for each of the
six types of variables. Currently, the BASIC
program that is to be processed must first be
saved in listing format and then read as a data
file. Benson’s cover letter stated that he was
working on a newer version that would work
with the 2040 disk and overcome this require-
ment.

For now, you must use a tape file so that the
program can take a long time to run. I took

PROGANAL 3/10/88

CURSOR CODES RRE NOTED IN BRACKETS WITH
NO. OF REPEATS. GRAPHIC CODES ARE ASCII

CLEAR =CC3 LEFT =C L D RIGHT =CR3

HOME =C H ] UP =C U 3 DOWN =C D 3

DELETE =C T 3 REVERSED V 3 OFF =C0 3

GRAPHICS G 3 BLANK =C B X SHIFTED >

«< LISTING »>

100 : P0KE59468 ,14

101 IFPEEK< 1022 >=8THENP0KE 1022, 128

1 05 G0SU64 1 00 : A=5 : B*=25 : C*=60

106 D*=65:E*=80:F*=40:K*=C*

1 10 DIMA* B*,A >,B* B*, A >,C* B*,3 >

111 DIMD*B*,3>,E*B*,3>,F*B*,2>

112 DIMG*D*,1 >,H*D*,2),I*B*,3>

113 DIMJ* A >,R* 300 >, V* 15 >

1 1 5 FORA=0TOD* : READG* A,0 >: NEXT

121 C4$=CHR*30>:C8*=CHR*29>

122 CQ*=CHR*34>

125 E$=CHR* 28 >+»C L 3C R 3C U 3C D 3C C 3C H 3C V 3C
0 3CB3"

126 F#=" TLRUDCHVOB

1 28 FORA= 1 TOE* : I $= I *+ - - - : NEXT

130 L*=” : L 1 $=L$+L$+L$+L$-H_$

135 L6S=" " : K$=L6S+L6*+ " L D DC 2

B3 M

1 4© GOSUB7008 : 0PEN3 , 3 : 0PEN4 , U
150 PRINTL6$L6*L6$L6$

155 IFIN=0THENPRINT"C VDPUT DATA TAPE IN
TRPE # 1 " : G0SUB295© : 0PEN2 ,1,0

PROGRAM:

PROGANAL 3/10/80

160 I F I N= 1 THENGOSUB 1 800
165 J=4: P=-l : 0=35: GOSUB3008
1 70 I FPT=0ANDU >3THENGOSUB7500
175 A*=“ LISTING"

180 I FJOB=0TH£NA*=" EXPANDED "+A*: IFPT=0
THENM= 1

1 85 GOSUB3200 : G0SUB2998 : A*= ■ " : TS=T I
190 :P*=‘‘ " :S$=" V$=" "

195 :W*=”:“

200 :C*=W*

210 : GET#2,W*: IFW$=CHR$< 10 >THEN210
220 I FW*=CHR* 1 3 >THENQ=0 : GOTO400
230 P$=P*+W$

248 I FW$=CQ$ANDQ= 1 THENQ=0 : WS=": G0T029

0

250 I FW*=CQSTHENQ= 1 : GOTO 1 95
260 I FQ= 1 THENGOSUB600 : GOTO200
270 IFW*<= M ! "THEN210
280 I FW*= “ : " THENGOSUB300
290 :V*=V*+US:GOTO200

%***

300 : N I =N I + 1 : I F JOB= 1 THENRETURN
3 10 S*=S*+P$ : 2= VAL< S S >

320 : I F VALC P$ > >0THENP$=M ID* L*+P* , LEN< S
TR* Z > >+2 >: I FF=0THENF=Z
330 I FLEN< PS X =F**MTHEN360
340 P*=LEFT* P$,F**M >+L#+" "+MID* P$,F*
*M+1 >: IFLEN< P* X =E**MTHEN360
350 P$=LEFT*P$,E**M>+L$+" "-H1ID* P$,E*
*M+1>

360 :PRINT#4,P^: IFLEN< P* »F*^MTHENO=0+l
: IFLEN< P^ >>E**MTHENO=0+l

- PAGE 2 -

Example 1. Sample Proganal output.

PROGANAL 3/10/80

«< STRING VARIABLES »>

m

7370

8020

8030

8040

8045

8050

w$

8O60

8110

X*

500 710 740 810 820

1260

1270

X*

1300

1320

1330

1350

1520

3660

x$

8090

8110

8210

8240

8250

Y*

700 740 750 770 780

ro

1310

Y$

1330

1350

z*

1570

1620

1640

1650

8120

8130

z*

8150

8180

8L90

«< NUMERIC ARRAYS »>
-NONE-

«< STRING ARRAYS

»>

A$<

110

2110

2240

6030

6050

&*<

110

2120

2250

6130

6150

C$<

110

2140

2270

6230

6250

D$<

111

2150

2280

6330

6350

E$<

111

2130

2260

6430

6450

F$<

111

930 6645

PROGANAL 3/10/80

«< MNEUMONICS »>

24

LEFT$<

26 LENC

LET

2

LIST

LOAD

LOGC

42

MID$<

NEW

35

NEXT

NOT

3 ON

6

OPEN

33

OR

2 PEEKC

3

POKE

POS<

114 PRINT

3

READ

6

REM

1 RESTORE

57

RETURN

15

RIGHT*<

RNDC

RUN

SAVE

SGNC

SINC

SPCC

SQRC

4

STEP

1

STOP

27 STR$<

SYS

3

TABC

r an<

192

THEN

33

TO

USRC

37

VALC

VERIFY

WAIT

UNKNOWN

«< BRANCH INSTRUCTIONS »>

190

400

418

195

250

520

200

260

290

210

210

270

290

240

300

280

320

440

360

330

340

400

220

470

440

550

420

500

600

260

638

610

1280

PROGRAM:

PROGANAL 3/10/80

«< AN ALAS I S SUMMARY »>

488 PROGRAM LINES < 1-10090 >
1033 INSTRUCTIONS
1433 TOTAL VARIABLES
92 VARIABLE NAMES
233 BRANCHES
19C LOGIC DECISIONS
37* RELATIVE COMPLEXITY
MINUTES TO PROCESS: 129.783056

12 Microcomputing, October 1980

over two hours to analyze 500 program lines.
But with unlimited computer time on your own
system, why worry about running time?

Proganal was written with an original 8K
PET with new ROMs, a 32K Expandapet and
an Axiom EX-801 printer connected to a
TNW-2000 interface. Several examples of what
you can expect as output are shown in Example

1. For more information, send a self-ad-
dressed, stamped envelope to Benson Greene.
He provides copies on tape with documentation
for $10.

Paper-Mate Command 60

Several months ago, AB Computers of
Montgomeryville, PA, announced its Paper-
Mate Command 60 word processor package
for the PET. Written by Michael Riley, this
package is an interesting program at a selling
price of only $29. It incorporates full-screen
editing with graphics for all 16K or 32K PETs,
with tape or disk drives and any printer. It in-
cludes many features of the Commodore Word
Pro 3 word processor, plus several new fea-
tures.

Written in BASIC, Paper-Mate is slower
than Word Pro 3. Since Word Pro 3 is written
in machine language, it can keep up with even
the fastest typist when entering text. However,
you must watch your typing speed with Paper-
Mate, or you will overrun the BASIC input
buffer. On the other hand, Paper-Mate can
easily be modified or customized to suit your
specific taste. The documentation even includes
a brief program outline and a list of all BASIC
variables used by the program.

For writing text, Paper-Mate has a definable
keyboard, so you can use it with either business
or graphics machines. You can even use your
graphics keyboard in a business keyboard
mode, where the top row of keys produces
numbers, and the semicolon key produces a pe-
riod. This makes typing with the graphics key-
board much smoother and faster. Another nice
feature is a shift lock for letters only, or you can
use the normal keyboard shift lock.

Text-editing features include floating cursor,
scroll up or down, page forward or back and re-
peating insert and delete keys. Text block han-
dling includes transfer, delete, append, save,
load and insert. The editing features are not as
outstanding as those in Word Pro 3, but they
get the job done.

All formatting commands are embedded in
the text for complete control, but commands
must be entered on a separate line.
Paper-Mate’s commands include margin con-
trol and release, column adjust, nine tab set-
tings, variable line spacing, text justification,
text centering and auto print form letters (vari-
able blocks). Files can be linked so that one
command prints an entire manuscript. Auto
paging, page headers, page numbers, pause at
end of page and hyphenation pauses are also in-
cluded. The hyphenation pause gives you the
option of either placing the separating hyphen
in a long word that overflows a line or keeping
the entire word intact on the next line.

With this word processor, you can use PET
graphics, as well as text. It can send any specific

ASCII code to the printer. This allows multi-
ple-expanded print on a Commodore 2022/
2023 printer, something that Word Pro 3 does
not support.

The following examines several features pro-
vided by Word Pro 3 but not supported by Pa-
per-Mate, or provided in a limited manner.

1. You cannot display the disk directory if
you are using a CBM 2040 disk for file storage.
However, you can send any other command to
the 2040 disk over the disk command channel.

2. There are no search or replace features.

3. Page numbers must be at the bottom of
the page. They cannot be selectively used in
headings, text, etc.

4. Only a single page heading is generated,
centered on the top of the page. Word Pro 3 al-
lows left, middle and right fields within the
heading— each positioned accordingly in the
heading line.

5. You cannot combine commands on a sin-
gle line; each Paper-Mate command must be on
a separate line.

6. When editing text, you must use the cursor
up/down keys to move from line to line. The
cursor left/right keys do not wrap from line to
line, as in the Word Pro 3.

The Paper-Mate program is a good, usable
word processor for the occasional user, con-
sidering its lower cost. However, I still recom-
mend Word Pro 3 for anyone requiring exten-
sive controls and fast response.

Light Pen Programs

In a recent column I mentioned Quill Soft-
ware of 2512 Roblar Lane, Santa Clara, CA
95051, as a source of programs for use with the
3G Light Pen. They currently offer six different
tapes, each with two programs.

Swords and Sorcery — An adventure game
using the light pen to fight trolls, find gold, etc.
An extensive version that barely fits in 8K. A
separate introduction program uses plenty of
graphic effects to explain general tactics.

Darth Vader and Hunt the Wumpus— Lo-
cate Darth Vader with your laser light beam or
hunt the Wumpuses in a much handier fashion.

Laser Shoot and Light Pen Keyboard— In
Laser Shoot, you point at a moving cursor to
fire at various targets. It’s complete with sound
effects as well as graphics. The other program
draws a replica of the PET keyboard for use as
an excellent light pen demo.

Othello and Owari — Play against the com-
puter using the light pen to select your moves.

Quill Quiz — Multiple-choice quizzes to test
your knowledge of states/capitals, Spanish/
English, vocabulary and historical dates/
events.

Billiards and Hangman— Play billiards using
the light pen as the cue. In Hangman, use the
light pen to save the victim or watch him climb
the scaffold and hang.

Quill Quiz is one of the best quiz-type pro-
grams I’ve seen. Answers are selected by simply
pointing the light pen at a flashing box next to
the answer. You can even select the number of
choices (up to ten). You can also determine the
question-answer format. For example, choose
the state that matches a given capital, or choose

the capital that matches the given state.

This program looks as if it could easily be
changed to provide quizzes for new topics. All
the data is contained in DATA statements, and
the program itself is very straightforward.

Each tape sells for $20, plus $1.50, handling.
Be sure to specify whether your system has the
old or new ROMs.

CMS Business Software

Over the past several months I’ve thoroughly
tested a business software package from Chuck
Stuart at CMS Software Systems (5115 Mene-
fee Drive, Dallas TX 75227). The series of four
program packages— General Ledger, Accounts
Payable, Accounts Receivable and Payroll— is
structured around the time-tested and proven
series of business software systems developed
by Osborne and Associates. The programs pro-
vided by CMS are designed to fill the need for a
comprehensive accounting package for the
PET. Each program can either stand alone or
be integrated with the others in a total software
system, depending on your needs.

Designed with the first-time user in mind, the
programs lead the operator through verified
data entry, step by step. It is impossible to crash
a program due to operator error or invalid data
input. Design consistency has been maintained
from program to program to greatly increase
operator familiarity and confidence.

Documentation — normally a problem for
small-systems users — is provided by the com-
prehensive series of Osborne and Associates
user manuals. These three manuals total over
800 pages of detailed step-by-step instructions
written at three levels for DP department man-
agers, data entry operators and programmers.
A second set of manuals details any operations
not covered in the Osborne manuals and any
program changes made during conversion to
the Commodore system. Each program is pro-
vided on disk with complete documentation
packaged in a handsome, three-ring binder.
The features of the four packages include:
General Ledger

• holds up to 300 accounts.

• accepts up to 3000 transactions per month.

• includes cash disbursements, cash receipts
and petty cash journals for simplified data en-
try.

• maintains account balances for the present
month, quarter and year, as well as for three
previous quarters and the previous year.

• includes complete financial reports, includ-
ing trial balance, balance sheet, profit and loss
statement, cash receipts journal, cash disburse-
ments journal, petty cash journal and more.

• accepts postings from external sources such
as the Accounts Payable, Accounts Receivable
and Payroll packages. Price is $295.

Accounts Payable

• automatic application of credit and debit
memos.

• maintains complete purchase records for up
to 200 vendors.

• invoice file accepts up to 400 invoices.

• random-access file organization allows fast,
individual, record updating.

• multiple reports provide a complete audit

Microcomputing, October 1980 13

Address
Hex - Decimal

Purpose

E000

57344

Initialize editor

E003

57347

Get a key > return in ft

E006

57350

Input a line

E009

57353

Print a character in ft

E00C

57356

Interrupt handler

E00F

57359

Time update & keyboard scan

E012

57362

Interrupt exit

E015

57365

Clear- screen

E018

57368

Set text mode, upper/ lower case display

E01B

57371

Set graphic mode> upper oase/srarhics display

E01E

57374

Set CRT controller

E021

57377

Scro 1 1 screen down 1 l i ne

E024

57380

Scroll screen up 1 line

E027

57383

Scan keyboard

E02A

57386

Piny bell

E02D

57389

Set repeat -flay

E030

57392

Set top lett limit o-f scroll window

E033

57395

Set bottom risht limit o-f scroll window
Example 2. Screen editor system calls.

trail.

• check printing with full invoice detail.

• full invoice aging.

• automatic posting to general ledger. Price is
$195.

Accounts Receivable

• maintains invoice file for up to 300 invoices.

• accommodates full or partial invoice pay-
ments.

• customer file maintains purchase informa-
tion for up to 1000 customers.

• allows automatic progress billing.

• provides for credit and debit memos, as well
as invoices.

• prints individual customer statements.

• automatic posting to General Ledger. Price
is $195.

Payroll

• maintains monthly, quarterly and yearly cu-
mulative totals for each employee.

• payroll check printing with full deduction
and pay details.

• sixteen different reports, including W2 and
941 forms.

• complete job costing option with cumulative
totals and overhead calculations.

• random-access file organization for fast up-
dating of individual records.

• automatic posting to General Ledger. Price
is $350.

After using the General Ledger package in a
real-life application for several months, I can
say this is one of the best packages I’ve tried.
The programming includes many built-in fea-
tures and options too numerous to delineate.

If you have a sound interface, the program
can provide an error warning signal or a short
beep whenever a key is struck (audio verifica-
tion). Along with the main programs of the
package, several disk utilities are included for
disk copying, erasing (scratching) account files
or zeroing account totals.

CMS provides an update service that allows
you to return your original program disk and
receive a copy of the latest version for a small
handling charge. If necessary, you’ll also re-
ceive any utility programs required to update
your active disks without disturbing the ac-
counting data.

CMS Software also offers several elaborate
game programs for the 16K PET: Baccarat,
Backgammon, Blackjack, Checkers, Craps,
Cribbage, Go Moku, Othello, Quibic 4, Rou-
lette and Space Invaders. Backgammon and
Space Invaders cost $9.95 each; all other pro-
grams are $7.95 each.

Low-Cost Software

Russell Grokett, in cooperation with the
Jacksonville Area PET Society, has made
available a large amount of low-cost software
for the PET computer. Included are games, fi-
nance, ham radio, astronomy, music, graphics
and utility programs. Also being added are
four-voice music and visible memory graphics
programs. Most programs are available for on-
ly $1.50 each, plus a small postage fee. Send an
SASE to PET Library, 401 Monument Rd.
#123, Jacksonville, FL 32211, for a three-page
list of the programs available.

Programmatics Software, 71 Sargent Ave.,

Providence, RI 02906, has also announced a list
of software available for the PET. Many of the
game programs use joysticks, and a parts kit
will be available to build a simple interface for
the PET. Other programs include a Billboard
program with one-inch high characters and in-
put editing, controlled scrolling speed, etc.

I just released several programs of my own.
If interested in a list of PET programs and/or
products, send an SASE to Baker Enterprises,
15 Windsor Dr., Atco, NJ 08004.

Short Notes

Back in March the premiere of the new vari-
ety show “Pink Lady” featured a Commodore
PET as a graphic device during a sequence by
the musical group Blondie. A real-time spec-
trum analyzer was used to translate the musical
tones onto the screen, displayed as a fluctuating
bar graph. As far as anyone knows, this was the
television debut of the Commodore PET.

An article in the March 17 issue of Comput-
erworld described a specially adapted PET that
is being used by a gifted, but spastic,

14-year-old boy in Dublin, Ireland. The young
poet suffers from severe athetoid cerebral
palsy. He is unable to speak and has almost no
control of his movements. With the aid of the
PET and specially prepared software, he can
now write, select, reread and edit his literary
material. Commands to the system are entered
using his chin or knees and specially designed
switches.

LRC, Inc., of Riverton, WY, has announced
a new printer for the PET for under $400. The
model 7000+ provides 40 characters per line
with a print speed of 1.25 lines per second. An
available option provides 64 characters per line.
This impact printer uses standard, low-cost roll
paper.

One of our readers passed on this word of
caution: If you order an Excel printer, be sure
the unit has been tested. A printer received back
in February apparently had an incorrect ROM
set and printed in Kata Kana, Japanese
phonetic characters. I should mention, how-
ever, that Excel promptly refunded the money
for the unit when it was returned.

A list of screen editor system calls for anyone
with a new 8016 or 8032 CBM with version 4,
disk BASIC is shown in Example 2.

14 Microcomputing, October 1980

Natural Organic Apple Software

Educational, intriguing and challenging. . .naturally!

Paddle Fun

This new Apple disk package requires a
steady eye and a quick hand at the game pad-
dles! We’ve included four different games to
challenge and amuse you. They include:
Invaders -You must destroy an invading fleet
of 55 flying saucers while dodging the carpet
of bombs they drop. Keep a wary eye for the
mother ship directing the incursion. Your
bomb shelters will help you -for a while. Our
version of a well known arcade game! Re-
quires Applesoft in ROM.

Howitzer - This is a one or two person game in
which you must fire upon another howitzer
position. This program is written in HIGH-
RESOLUTION graphics using different terrain
and wind conditions each round to make this a
demanding game. The difficulty level can be
altered to suit the ability of the players. Re-
quires Applesoft in ROM.

Space Wars - This program has three parts: (1)

Two flying saucers meet in laser combat — for
two players, (2) two saucers compete to see
which can shoot out the most stars - for two
players, and (3) one saucer shoots the stars in
order to get a higher rank - for one player only.
Requires Applesoft.

Golf -Whether you win or lose, you’re bound
to have fun on our 18 hole Apple golf course.
Choose your club and your direction and hope
to avoid the sandtraps. Losing too many
strokes in the water hazards? You can always
increase your handicap. Get off the tee and on-
to the green with Apple Golf. One of its nicest
features is you’ll never need to cancel a golf
date due to rain. Requires Applesoft.

The minimum system requirement for this
package is an Apple II or Apple II Plus com-
puter with 32K of memory and one minidisk
drive.

Order No. 0163AD $19.95

1234567890 %

Math Fun

Apple Fun

We’ve taken five of our most popular pro-
grams and combined them into one tremen-
dous package full of fun and excitement. This
disk-based package now offers you these
great games:

Mimic — How good is your memory? Here’s a
chance to find out! Your Apple will display a
sequence of figures on a 3x3 grid. You must
respond with the exact same sequence, within
the time limit.

There are five different, increasingly difficult
versions of the game, including one that will
keep going indefinitely. Mimic is exciting, fast
paced and challenging -fun for all!

Air Flight Simulation - Your mission is to take
off and land your aircraft without crashing.
You’re flying blind: on instruments only.

You start with a full tank of fuel, which gives
you a maximum range of approximately 50
miles. The computer will constantly display
updates of your air speed, compass heading
and altitude. Your most important instrument
is the Angle of Ascent/Bank Indicator. It will
tell if the plane is climbing or descending and
whether banking into a right of left turn.

After you’ve acquired a few hours flying
time, you can try flying a course against a map
or doing aerobatic maneuvers. Get a little
more flight time under your belt and the sky’s
the limit!

Colormaster — Test your powers of deduction
as you try to guess the secret color code in this
Mastermind-type game. There are two levels of
difficulty, and three options of play to vary your
games. Not only can you guess the computer’s
color code, but it will guess yours! It will also
serve as referee in a game between two human
opponents. Can you make and break the color
code. . .?

Star Ship Attack -Your mission is to protect
our orbiting food station satellites from
destruction by an enemy star ship. You must
capture, destroy or drive off the attacking ship.
If you fail, our planet is doomed.

Trilogy -This exciting contest of logic has its
origins in the simple game of tic-tac-toe. The
object of the game is to place three of your col-
ors in a row into the delta-like, multi-level
display. The rows may be horizontal, vertical,
diagonal and wrapped around, through the
“third dimension”. Your Apple (or human oppo-
nent) will be trying to do the same, and there
are many paths to victory. You can even have
your Apple play against itself!

Minimum system requirements are an Apple
II or Apple II Plus computer with 32K of
memory and one minidisk drive. Mimic re-
quires Applesoft in ROM, all others run in RAM
or ROM Applesoft.

Order No. 01 61 AD $19.95

Change an Apple computer jnto a
mathematics tutor and change boredom into
enthusiasm with the Math Fun package. Using
the technique of immediate positive reinforce-
ment, students can improve their math skills
while playing a game with:

Hanging- A little man is walking up the steps
to the hangman’s noose. But YOU can save
him by answering the problems posed by the
computer. The program uses decimal math
problems. Each correct answer will move the
man down the steps and cheat the hangman.
Spellbinder -You are a magician competing
against a computerized wizard. In order to cast
death clouds, fireballs and other magic spells
on him, you must correctly answer questions
about using fractions.

Whole Space - Pilot your space craft to attack
the enemy planet. Each time you give a correct
answer to the whole number problems posed
by the computer, you move your ship. But for

every wrong answer, the enemy gets a chance
to fire at you.

Car Jump -Make your stunt car jump the
ramps. Each correct answer will increase the
number of buses your car must jump over.
These problems involve calculating the areas
of different geometric figures.

Robot Duel — Fire your laser cannon at the
computer’s robot. If you give the correct
answer to problems on calculating volumes,
your robot can shoot at his opponent. If you
give the wrong answer, your shield power will
be depleted and the computer’s robot can
shoot at yours.

Sub Attack -Practice using percentages as
you maneuver your sub into the harbor. A cor-
rect answer lets you move your sub and fire at
the enemy fleet.

All of these programs run in Applesoft
BASIC, except Whole Space, which requires
Integer BASIC.

Order No. 0160AD $19.95

TO ORDER: Look for these programs at the dealer nearest you. If your store doesn't
stock Instant Software send your order with payment to: Instant Software, Order Dept.,
Peterborough, N.H. 03458 (add $1.00 for handling) or call toll-free 1-800-258-5473
(VISA, MC and AMEX accepted).

Instant Software

Prices subject to change without notice.

PETERBOROUGH, N.H. 03458
603-924-7296

Microcomputing, October 1980 15

Walter Koetke

COMPUTER BLACKBOARD

10 REM STUDENT NAMES - VERSION 2
20 CLS J RESTORE X M=0 : PRINT

30 PRINT "PLEASE TYPE YOUR FIRST NAME " * X INPUT N$

40 READ Fit L$

50 IF F$=-XXXX“ THEN 90
AO IF F*ON* THEN 40

70 IF M=0 THEN PRINT "YOUR LAST NAME MUST BE * L$ X M=1 X GOTO 40
80 PRINT TAB ( 20 ) 'OR - L* X GOTO 40

90 IF M=0 THEN PRINT 'YOU DON'T BELONG IN THIS CLASS* 1
100 PRINT 0976* 'PRESS THE C-KEY TO CONTINUE’*

110 X$=INKEY$ X IF X$<>-C- THEN 110
120 GOTO 20

300 DATA BARRY* WATERS* TOM* JONES* RHONDA* STEWART
310 DATA TOM* SMITH* ALICE* PETERS* CAROL* ALLEN
320 DATA CAROL* WILSON* BILL* HARRIS* TOM* MCNALLY
330 DATA DAVID* OLSON* DANIEL* SMITH
390 DATA XXXX* XXXX

Listing 2.

Dealing with Educational Realities

The person who writes a program almost cer-
tainly learns more than the person who uses
that program. This is readily apparent regard-
ing the learning of programming skills. It is also
equally valid regarding the game, simulation,
drill or problem that is being programmed.

Consider, for example, a program that
begins by asking a student to think of any coun-
try in the world. After asking the student a few
geographically-based yes/no questions, the
program will correctly identify the country
selected by the student. I’ve observed the use of
this program by a third grader who used an
atlas before answering many of the questions.
The boy was obviously enjoying himself while
learning world geography and developing map-
reading skills. This was a marvelous use of a
well-written program that certainly would have
warmed the heart of the person who wrote the
program.

Nevertheless, the program author learned a
good deal more geography than the third-grade
user. The author had to first identify all of the
countries in the world. This is a nontrivial, real-
time task on which reputable authorities appear
to disagree. The author then had to write the
yes/no questions that would enable the pro-
gram to uniquely identify each country. This
was followed by the task of creating a program-
mable procedure that would provide all of the
desired interaction. Finally comes writing, typ-
ing and debugging the actual program code.

There’s an important message in this exam-
ple. Whenever possible, let the students write
their own programs. The microcomputer is a
magnificent “what if’’ machine. Students
should always be encouraged to experiment
with their ideas. They should never just
wonder, “What if I do this or that?’’ They
should do it and experience the consequences.
The computer cannot be harmed or even in-

sulted by what is typed by a curious student.
What appears to be a major disaster can be
completely eliminated by turning the micro-
computer off and on again.

This message— that students should be en-
couraged to write their own programs— is easi-
ly lost when you visit your local computer store,
watch a demonstration, explore the pro-
grams in an educational resource center or even
read a magazine. There are over 500 software
vendors currently competing to sell you pro-

PLEASE TYPE YOUR FIRST NAME? RHONDA
YOUR LAST NAME MUST BE STEWART

PLEASE TYPE YOUR FIRST NAME? TOM
YOUR LAST NAME MUST BE JONES
OR SMITH
OR MCNALLY

PLEASE TYPE YOUR FIRST NAME?

Sample run 1.

grams. Some of these vendors have a few sound
products appropriate for education. Almost
none of them have products that can be used
while a student is using the microcomputer to
write his own program. Thus, there is a heavy
commercial emphasis on already written pro-
gram packages.

I encourage you to examine these packages
and buy the better ones. But never lose sight of
today’s most significant microcomputer ap-
plication — students writing their own pro-
grams.

Although you may be personally convinced
of the validity of the preceding sermonette, the
realities of your school situation may not per-
mit its full implementation. After all, a student
uses considerably more computer time pro-
gramming and debugging than another who
merely runs an educationally sound program
prepared by someone else. Let’s take a look at a
couple of typical situations that aren’t very sup-
portive of each student writing his own pro-
gram and some alternate solutions.

Consider the elementary school principal
who is convinced that computer literacy must
be incorporated into the curriculum for each of
his 600 students. This principal is also commit-
ted to equal opportunities for all of his
students. He does not want microcomputers to
become the exclusive province of a small group
of teachers or students. As you and I nod our
heads in agreement with his goals, he throws a
curve.

How can his students begin to achieve com-
puter literacy with just one or two microcom-
puters? After considering several possibilities,
the principal requested that a program be
written to implement the following plan. He
hoped to put a microcomputer in the hall out-
side his office with the program already
loaded and running. One morning he would an-
nounce that each first grader should type his

10 REM STUDENT NAMES - VERSION 1
20 RESTORE X M=0 X PRINT

30 PRINT ’PLEASE TYPE YOUR FIRST NAME'* X INPUT N$

40 READ Fit Li

50 IF F$= " XXXX " THEN 90

60 IF FK>N$ THEN 40

70 IF M=0 THEN PRINT "YOUR LAST NAME MUST BE - Li l M=1 J GOTO 40
80 PRINT -OR ' Li X GOTO 40

90 IF M=0 THEN PRINT 'YOU DON'T BELONG IN THIS CLASS.-
100 GOTO 20

300 DATA BARRY* WATERS * TOM* JONES* RHONDA* STEWART
310 DATA TOM* SMITH* ALICE* PETERS* CAROL* ALLEN
320 DATA CAROL* WILSON* BILL* HARRIS* TOM* MCNALLY
330 DATA DAVID* OLSON* DANIEL* SMITH
390 DATA XXXX* XXXX

Listing 1.

16 Microcomputing , October 1980

10 REM DRILL AND PRACTICE — FOR ANY SUBJECT AREA
20 CLS J READ N l DIM W(N)

30 C=0 J FOR 1=1 TO N J W(N)=0 J NEXT I

40 PRINT "HOW MANY REVIEW QUESTIONS WOULD YOU LIKE"? : INPUT R

50 FOR K=1 TO R

60 CLS : RESTORE t READ N* Qt

70 P=RND(N) J IF W(P)=1 THEN 70

80 W<P)=1 J T=0

90 FOR 1=1 TO P J READ A$* B* l NEXT I
100 PRINT J PRINT Q$? A*? ♦ INPUT R$

110 IF R$=B$ THEN PRINT "CORRECT" X C=C+1 t GOTO 140
120 IF T=0 THEN PRINT "NO* TRY AGAIN ♦ " ♦ T=1 ♦ GOTO 100
130 PRINT "NO* THE ANSWER IS " ? B*

140 PRINT @976* "PRESS THE C-KEY TO CONTINUE"?

150 X*=INKEY* ♦ IF X$<>*C" THEN 150
160 NEXT K

170 CLS X PRINT "YOU ANSWERED" C "OF" R "REVIEW QUESTIONS CORRECTLY."

300 DATA 10 f WHO IS THE COMPOSER OF

310 DATA YELLOW SUBMARINE * BEATLES

320 DATA SWAN LAKE* TCHAIKOVSKY

330 DATA STARS AND STRIPES FOREVER » SOUSA

340 DATA THE BRANDENBURG CONCERTOS * BACH

350 DATA THE NEW WORLD SYMPHONY > DVORAK

360 DATA 50 WAYS TO LEAVE YOUR LOVER * SIMON

370 DATA CAMELOT * LOWE

380 DATA OKLAHOMA * RODGERS

390 DATA 76 TROMBONES* WILLSON

400 DATA PETER AND THE WOLF* PROKOFIEV

Listing 3.

RUN

HOW MANY REVIEW QUESTIONS WOULD YOU LIKE? 4

WHO IS THE COMPOSER OF THE BRANDENBURG CONCERTOS? BACH
CORRECT

WHO IS THE COMPOSER OF YELLOW SUBMARINE? EAGLES
NO* TRY AGAIN.

WHO IS THE COMPOSER OF YELLOW SUBMARINE? BEATLES
CORRECT

WHO IS THE COMPOSER OF 50 WAYS TO LEAVE YOUR LOVER? SIMON
CORRECT

WHO IS THE COMPOSER OF CAMELOT? SOUSA
NO* TRY AGAIN.

WHO IS THE COMPOSER OF CAMELOT? RODGERS
NO* THE ANSWER IS LOWE

YOU ANSWERED 3 OF 4 REVIEW QUESTIONS CORRECTLY.
READY

Sample run 2.

first name on the computer “just to see what
happens.* * He wanted the program to respond
by displaying the last name of the student.
After two or three days, he would make the
same announcement to the second grade, and
so forth.

The initial version of a program that met
these requirements was written by a fourth
grader in another school. See Listing 1 and
Sample run 1 .

That’s all there is to it. By changing the
DATA statements, you can make the program
apply to your class. You might also add nick-
names so the computer can identify students by
first name or nickname. For example, if Tom
Smith’s nickname is Ferd, then the DATA
statements would contain both FERD, SMITH
and TOM, SMITH. Alternately, the student
might enter his full name and have his address
displayed or enter his phone number and have
his name or date of birth displayed.

Remember to use “XXXX”, “XXXX”
(now in line 390) as the final two items in the
DATA statements, because the program uses
this as an indicator that there are no more
names in the list. Be careful when entering the
DATA lines of this program. If you misspell a
student’s name, he is going to feel badly when
the computer is unable to identify him.

As is the case for virtually all programs, this
one can be improved. One improved version
for the TRS-80 is illustrated in Listing 2. Note
that the changes (lines 20, 80 and 100-120) are
all user oriented. They provide a more attrac-
tive display and a reduced chance of student
confusion. Should you use the program, you’ll
probably make additional improvements of
your own.

Return for a moment to the hallway and the
first graders entering their first names. Use of
this program accomplished several things.
Students and teachers alike learned they could
touch a computer without harming themselves
or the machine. Student interest was very high.
They wondered, “How did it know my name?
What else does it do? How does it print so
fast?”

As a necessary part of his goal regarding
computer literacy, the principal distributed
copies of the entire program to the students
during the week following their first computer
experience. What did they see? They saw a few
lines of BASIC that they didn’t yet understand,
followed by the first and last name of every stu-
dent in their grade.

Then several important ideas became ap-
parent. The computer uniquely identified
Rhonda because there’s only one Rhonda in
first grade. Tom was given three possibilities
for his last name because there are three Toms
in the first grade. The students learned that the
computer can process data very rapidly. But the
computer does not know anything we haven’t
told it. That’s an important idea on the road to
computer literacy.

Now consider an altogether different situa-
tion. Suppose you are completely convinced
that students should write their own programs
whenever possible. However, educational reali-
ties require that you convince other teachers of
a variety of subject areas that the computer will
also be useful to them. This is a rather common
political situation for teachers in many schools.

Let’s examine a single program that can be
used in nearly all subject areas, although in this
instance the program is adapted to music. (See
Listing 3 and Sample run 2.) This program is a
no-frills drill and practice exercise, but its ver-
satility just might help convince others that mi-
crocomputers are useful. Check last month’s
article for one appropriate use for this type of
program.

Briefly, the program selects a question at
random from those in the DATA statements. If
the student answers a question correctly, an-
other question is randomly selected. If a ques-
tion is answered incorrectly, the question is re-
peated. If the question is answered incorrectly
again, the right answer is given and the next
question is selected.

There are several aspects of this program
worth noting. Although rather brief, it contains

several features that might be included in your
own drill and practice routines. Line 40 permits
the student to enter the number of questions de-
sired. This is helpful, since all students don’t re-
quire the same amount of review. This feature
also makes the program usable within the
changing time constraints of the classroom.

Lines 70 and 80 ensure that the randomly se-
lected questions will not be repeated during a
single session. The variable T in lines 80 and 120
is used to indicate how many times a question
has been incorrectly answered. This can be easi-
ly modified to allow additional tries before the
correct answer is given.

Lines 130-150 allow the student to proceed
at his own rate. A question and the correct
answer are only cleared from the screen when
the student indicates he is ready to continue.

If you don’t understand lines 10 through

Microcomputing, October 1980 17

300 DATA 8 » WHICH WORD IS THE NOUN —

310 DATA BILL RAN FAST** BILL

320 DATA THE HORSE WAS TIRED » * HORSE

330 DATA A SMART PERSON IS THINKING ♦ t PERSON

340 DATA THE RACE WAS CLOSE *r RACE

350 DATA CANDY IS SWEET!* CANDY

360 DATA THE PROBLEM IS SOLOED ♦ t PROBLEM

370 DATA MY PENCIL IS SHARP ♦ t PENCIL

380 DATA COMPUTERS ARE FUN TO USE ! r COMPUTERS

Listing 4.

170, that’s OK for now, but you should try to
eventually understand them. Line 300 is special
since it contains the number of questions and
answers (only ten in Listing 3), as well as the
common portion of each question. DATA lines
from line 3 10 to the end of the program contain
each of the questions and answers that might be
selected in the drill.

The most important feature of this program
is that it provides you with the ability to com-
pletely change not only the questions, but also
the subject area and question format by merely
retyping the data lines. For example, Listing 4
illustrates data for a drill that might be ap-
propriate for an English teacher, while Listing

5 illustrates data for an elementary school
mathematics lesson.

Don’t be misled by the brevity of these ex-
amples. A 16K microcomputer with just cas-
sette storage can hold hundreds of questions
and answers in a single program. A teacher who
takes the time to prepare a sizable number of
drill questions will provide students with an ef-
fective, comprehensive tool for review.

Remember that the student who writes a pro-
gram learns more than anyone who uses the
program. There are, however, many circum-
stances in which the programs of others can be
very helpful. Hopefully the programs in this ar-
ticle will help you address two very common

300

DATA

Ilf

TYPE THE MISSING NUMBER

310

DATA

2

4 - 8 f 6

320

DATA

217

- 219 220 f 218

330

DATA

27

30 33 - f 36

340

DATA

5

10 - 20 r 15

350

DATA

-

7 10 13 f 4

360

DATA

4

- 12 16 f 8

370

DATA

120

130 - 150 t 140

380

DATA

-

88 90 92 f 86

390

DATA

21

28 35 - f 42

400

DATA

27

36 - 54 f 45

410

DATA

15

- 31 39 f 23

Listing 5.

educational realities — serving many students
with minimum microcomputer availability and
demonstrating to other teachers that the
microcomputer can help them in their own sub-
ject areas. The second example goes even fur-
ther in that it demonstrates that teachers with
no programming skills can still tailor drills for
their students in precisely the fashion they
choose.

Correspondence concerning this column
should be addressed to Walter Koetke, Put-
nam/Northern Westchester BOCES,
Yorktown Heights, NY 10598.

BOOK REVIEWS

Optimization Techniques in FOR-
TRAN

Joel L. Sears
Petrocelli Books, Inc.

New York, 1979
90 pages, softcover, $10

The title of this book is a misnomer.

Optimization, taken in its usual context,
means to use some scarce resource of a machine
less frequently. This can be done through such
methods as making the program run faster or
requiring less primary storage.

But in most cases, Sears does not deal with
faster run times or less memory.

Programming Tricks in FORTRAN might
have been a more descriptive title.

Sears shows numerous ways to get more out
of your compiler than you can with most FOR-
TRAN dialects. Using sample programs and
clear explanations, he covers such topics as
character manipulations, input/output, inter-
nal documentation facilities and subprograms.

While the material is oriented toward FOR-
TRAN, many of the techniques can easily be
adapted to other programming languages. To
the FORTRAN programmer, this book can be
an invaluable aid.

To the non-FORTRAN programmer, this
book can help him get a little more out of his
translator.

W.A. Harrison
Rolla, MO

Digital Experiments, 2nd Edition

Richard E. Gasperini
Hayden Book Co., Inc.

Rochelle Park, NJ, 1978
192 pp., $8.95

This is essentially a workbook that will guide
you through 25 hands-on verification experi-
ments. These experiments are designed to ac-
quaint you with the operation of basic ICs and
LEDs, and teach how to power them, what the
pin connections look like, what kinds of out-
puts are obtained in response to various inputs
and how to connect them.

The experiments progress not only by the so-
phistication of the circuit but by the amount of
guidance given. The initial experiments are
highly structured, with few decisions required.
Later, you must look up your own pinouts. Fi-
nally, even the schematic must be worked out.

In the introduction you are told about a logic
lab, which is essentially a breadboard for ICs,

power supply, switches for data input, LEDs
for level indication and a slow and fast clock.

The book recommends how to buy labs or
lab kits, and gives sufficient circuitry and in-
structions for those who care to design and
build their own. It also makes recommenda-
tions regarding the acquisition of a logic probe,
pulser and other equipment to carry out the ex-
periments in this book. Seventeen different
types of ICs and LEDs to be studied in these ex-
periments are listed.

All the data sheets required for these ICs and
more are furnished in an extensive appendix.
Other appendices furnish data sheets on the
LEDs, IC cross-references and sources of ICs.

Gasperini includes everything necessary to
get the beginner started. If you choose to build
your own lab, as you might after reading the
recommendations, you will find not only that
you have a better lab at far less cost, but also
that your digital education is already well-un-
derway.

The experiments start with the measurement
of logic levels. They continue by studying the
operation of the 7404 hex inverter, what hap-
pens when input leads are left open and trou-
bleshooting. Experiments 3 to 6 cover the oper-
ation of the AND, NAND, OR and NOR gates,
and 7 covers LEDs. Following this, the book
discusses decoders in general, and studies a
BCD to decimal decoder. Since multiplexers

18 Microcomputing , October 1980

are somewhat related, they are treated next. Ex-
periment 10 covers the exclusive-OR as a com-
parator and as a programmable inverter.

Starting with Experiment 1 1 , you are forced
to determine your own pin connections (from
the data sheets appendix). The next few experi-
ments study the interconnection, operation and
use of various kinds of latches and flip-flops.
These are followed by several styles of coun-
ters, drivers and displays.

Each of these experiments is well thought
out, and you are supplied with definitions, ex-
planations and diagrams. It would be hard to
go wrong.

In Experiment 23 the reader is closely guided
through the connection and operation of a ran-
dom access memory. In Experiment 24, you are
encouraged, with some guidance, to connect
and operate a digital clock, using many of the
ICs studied in the previous exercises. The last
experiment is totally unstructured.

It is difficult to review this book without
mentioning another book by the same author,
on much the same subject. Digital Trouble-
shooting contains a great deal of very practical
digital theory that would very nicely augment
the theory given in Experiments. I recommend
that you use the books together.

This book, along with its companion, is one
of a growing number that start at a beginner’s
level and progress toward something more
complicated. While many attempts fall short,
this one does not. The book is easy to read and
thoroughly enjoyable to work with, and I high-
ly recommend it.

Alfred Adler, Ph.D.

Tucson, AZ

Computer Systems Organization
and Programming

Harry Katzan, Jr.

Science Research Associates, Inc.

Chicago, IL 1976
Hardcover, 459 pp., $17.95

Many books cover a specific topic in great
detail. But sometimes the computerist wants a
more general survey of the many aspects of
computer systems and programming. Comput-
er Systems and Organization is just such a
book.

It starts off with an introduction to algo-
rithms, sequential machines and grammars,
and progresses to programming languages and
computer architecture. It discusses in detail the
processing unit, main storage and input/output
organization, and covers number systems,
complement arithmetic, internal data represen-
tation, structures, lists and arrays.

The book provides a good introduction to
general machine language. In addition, it cov-
ers programming techniques, including string
manipulation and list processing operations.

An introduction to computer software sur-
veys assemblers and discusses their relation to
monitors and linkage editors. A section on pro-
gramming techniques introduces macros, pre-
sents the relation of chaining, overlaying and
common storage to the machine and structured
programming and provides a thorough treat-

ment of subprograms.

Two chapters on data management intro-
duce external storage devices, file structures,
storage device technology and data manage-
ment functions, and end with a condensed
treatment of data base concepts.

The author also deals with operating systems
and their functions. He discusses operating sys-
tem organization, scheduling, allocation, inter-
rupt control and virtual storage methods.

This month, we are pleased to introduce our
readers to “Micro Quiz, ” a new column that
will be appearing regularly in the pages o/Kilo-
baud Microcomputing. The column appears
through the efforts of Marc Brown, director of
the New England Computer Science League
(NECSL), which administers monthly comput-
er contests for high-school students.

Each month, Marc will test Kilobaud Micro-
computing readers with programming prob-
lems and computer questions — varying in de-
gree of difficulty — taken from previously held
NECSL contests. Answers will appear in the
back pages of the same issue.

To help you better understand the source of
the questions used in this column, we have in-
cluded a brief profile of the history and activi-
ties of the NECSL.

Organized in 1978, the New England Com-
puter Science League (NECSL) conducts con-
tests for high -school students and awards prizes
to outstanding students and schools on local
and regional levels.

NECSL motivates students to study comput-
er topics not covered in their school’s curricu-
lum and to pursue classroom topics in depth. It
encourages students to exchange intellectual
ideas and helps them to improve their computer
skills. It has already provided the impetus for
some high schools to expand and improve their
computing facilities and course offerings.

Contests are held simultaneously at each par-
ticipating school, and an unlimited number of
students from all grade levels may compete at
each school. A school’s score for each contest is
the sum of the scores of its five highest -scoring
students. In each contest, students are given
short theoretical and applied questions and
then a practical programming problem to solve
(within the following two days) using their
school’s computer facilities. After the contest is
administered by the faculty advisor, each
school’s results are returned to the League for
tabulation. At the completion of each year’s
contests, an all-star competition is held.

Short questions are designed to be both easy
and difficult. This encourages students from all
grade levels to participate. Much of the subject
matter is new to students, but the programming
problems are designed to be useful, practical
real-world applications.

Computer System Organization and Pro-
gramming is a good survey of organization and
programming, and does a good job of present-
ing the concepts that are essential for additional
study. But while the book seldom gets too de-
tailed, you should have a basic knowledge of
computers. This is not for neophytes.

It is also an excellent reference book.

Warren A. Harrison
Rolla, MO

Providing graduated test data is another ma-
jor appeal of the League. Novices can write
programs on simplistic levels to handle the first
few test data elements, while experienced pro-
grammers can write programs on sophisticated
levels to handle the more difficult test data ele-
ments.

High schools have chosen to implement
NECSL in many different ways. Some schools
that do not offer any computer courses have
used NECSL as the focal point for their com-
puter club. Some have used the contest materi-
als to supplement existing courses, and some
schools have even used NECSL as the outline
for an entire course in computer science.

The NECSL idea blossomed under the direc-
tion of Marc Brown, currently a graduate stu-
dent in Computer Science at Brown University
in Providence, Rhode Island. In its first year,
NECSL operated in an experimental mode only
in Rhode Island. It soon became apparent that
there was a tremendous need for a computer
science league, and the League then expanded
into the remaining New England states the next
year. Today, participation is open to all schools
throughout the entire country.

Currently, a handful of annual program-
ming contests exists throughout the United
States. NECSL is unique because its contests
cover many aspects of the science, not merely
programming, and contests are regularly held
each month, not yearly.

Queries regarding column questions or solu-
tions or the NECSL should be addressed to:
Marc Brown
NECSL
Box 1910
Brown University
Providence, RI 02912

Upon completion of the follow-
ing program, how many differ-
ent elements of array X will have
been accessed?

DIM X(10)

FOR J = 1 TO 6

READ A
X(A - J) = J
NEXT J

DATA 8, 3, 10, 6, 7, 7

answer on page 214

MICRO QUIZ

Microcomputing, October 1980 19

Edited by Dennis Brisson

NEW PRODUCTS

Panasonic’s Handheld Computer

The RL-H1000 is a modular handheld com-
puter (HHC) that features a full complement of
separate peripheral devices including an input/
output interface to attach up to six additional
peripherals, an acoustic coupler/telephone mo-
dem, cassette interface, video RAM interface
for hook-up to a home TV set, a mini printer
and RAM and ROM memory expanders. The
RL-H1000 accommodates four 16K, 32K, 64K
or 128K ROM capsules. Four additional cap-
sules can be added with a ROM expander mod-
ule. It has 65 re-assignable keys and a keyboard
overlay system. A complete ASCII character
set, in addition to the “help” key, makes tradi-
tional command programming easy. Three
user-definable function keys accommodate
specific capsule programs, multiple key se-
quences and specialized terminal functions. A
memory key allows entrance into RAM from
within any program and automatically selects
the proper RAM mode for each program. With
the four-direction window control, you can
drive anywhere within any program or memory
file.

A full matrix liquid crystal display graphics
panel is incorporated on the RL-H1000. It dis-
plays graphics, foreign alphabet characters and
proportional spacing, as well as full upper and
lowercase ASCII. A ten-speed display control
key gives information at varying rates of speed.

The RL-H1000 has a built-in RAM, so you
can store up to 500 characters for use as a por-

table, electronic memo pad. A self-contained
world time clock displays month, date, hour
and minute. The HHC has a programmable
timer with alarm and message function to work
as an electronic secretary. It is also compatible
with virtually every computer data bank via the
telephone modem/acoustic coupler.

Panasonic Company, One Panasonic Way,
Secaucus, NJ 07094. Reader Service number
483.

Socket- Wrap ID

Now you can easily identify pin numbers on
wire- wrapping sockets with the Socket- Wrap
ID from OK Machine and Tool Corporation,
3455 Conner St., Bronx, NY 10475. These
socket-sized plastic panels with numbered holes
in the pin locations can be simply slipped onto
the socket before wrapping. You can also write
on them for easy identification of location, IC
part number or function to simplify both initial
wire-wrapping and subsequent troubleshooting
or repair. Reader Service number 498.

Direct-Connect TRS-80 Modem

Lynx is a new direct-connect telephone
modem for the TRS-80 that eliminates the need
for a separate expansion interface, interface
board, telephone coupler and communications

OK Machine and Tool's pin number identifier.

software. It connects directly with the keyboard
and the telephone line; no acoustic coupler is
used. It includes originate and answer capabili-
ty and is programmable for word length, pari-
ty, number of stop bits and full or half duplex.
During data exchange, it automatically discon-
nects the local telephone handset, thus elimi-
nating room noise pickup typical of acoustic
couplers.

Minimum hardware requirements are a Lev-
el I or II with 4K RAM. Including a terminal
cassette program, instruction manual and
power pack, the Lynx costs $239.95.

Emtrol Systems, Inc., 1262 Loop Road,

Panasonic's HCC with peripherals.

The Lynx modem.

20 Microcomputing, October 1980

Instant SoftwaielNew Releases

FOR THE TRS-80*

LIFE

Would you like to play god?

Even if you’ve only been involved with com-
puters for a short while, you’re certain to have
heard of Life. The game was originally created
by British mathematician John Conway and
popularized in Martin Gardner’s Mathematical
Games column in Scientific American maga-
zine. Life, a computerized simulation of the life
cycle of a colony of bacteria, allows you to
manipulate both the bacteria and their environ-
ment.

Over the years the game has lost none of its
fascination for computerists. It is based on a
few simple concepts but it results in captivating,
animated graphics displays.

There are two versions of Life included in

this package. The first is written in machine-
language and is the most versatile, flexible and
the swiftest version of Life we’ve ever seen. The
second is in BASIC with machine-language
subroutines. This allows both the machine-lan-
guage devotee and the BASIC aficionado to ex-
periment with the program.

Patterns can be created and edited easily.
You can create your own “creatures” or use the
library of preprogrammed creatures. You can
run at full speed (100 to 200 generations per
minute), enter a pause factor, or single step
through the life cycle.

No matter how you approach Life, whether
artisitically, mathematically, intuitively, or just
for fun, this is THE classic program.

Order No. 0078R $9.95

Winner’s Delight

Are you a winner? Do you enjoy challenging
yourself with thorny tasks? Then try Winner’s
Delight. This quartet includes:

Amazing — You must escape from a maze, one
that you view from the inside. You must work
against the clock— and you may meet a nasty
dwarf who can block your passage to freedom.
Junior Checkers— Not your usual game of
checkers . . . The challenge is to beat the com-
puter in the fewest number of moves.

Jumbo Jigsaw — Fit the pieces of the jigsaw
together in the fewest number of tries. The pro-
gram offers three levels of expertise for you to
choose from.

Thirteen Ways — Try to fill up your columns
with the numbers you roll on dice. Lady Luck
may be with you or against you. But you may

be certain that the computer will be plotting
how to fill its columns first!

You too can be a winner, with Instant Soft-
ware!

Order No. 0124R $9.95

Body Buddy

Get to know the Inner You. Use this package
to learn your caloric needs and to set up a
weight-loss diet. It will also introduce you to
human anatomy and physiology.

The Adult Caloric Requirements program
can determine your Basal Metabolic Rate, after
you respond to a computerized “question-
naire”. Then the program makes recommenda-
tions on how you can reach an ideal weight,
through dietary planning.

Our Flexi-Diet program will create a prac-
tical diet for you. Choose your caloric intake,
from 600 to 2400 calories per day. The program
will make up sample menus for any meal you
desire. If you don’t care for its choices, it will
make as many alternative menus as you like!

In the Anatomy Quiz program, a human tor-
so is drawn on your video monitor and you
must locate various organs within the body.
After you’ve made your choice, the program
gives a mini-lesson, which includes the organ’s
size, exact location and major bodily functions.

Body Buddy: Let it change you for the bet-
ter!

Order No. 0109R $9.95

Instant Software

M

^40

Investor’s Paradise

Imagine that you’ve been given a large sum
of money and have the opportunity to see if you
can make a killing in the market . . .

Stock Trek — This is a stock market simulation
in which you and up to five other investors buy
and sell stocks. See if you can transform $5000
into a fortune in twelve short months. The pro-
gram has an automatic ticker tape that an-
nounces market conditions plus a stock price
display board. You can ask for a prospectus
that will describe each stock and its dividend
potential. Finally, you can see the performance
of each stock displayed on a graph. At the end
of one (simulated) year, the computer will
display the net worth of all investors. The
player with the greatest net worth is advised to
start looking at the financial pages.
Speculation — This program goes a step beyond
being a mere simulation. You enter the finan-
cial data on up to 25 real companies and start
playing the market. You can buy and sell shares
based on net cost, including sales commissions.
You’ll be able to compare how you did in the
market, based on the value of your portfolio
and accumulated dividends, versus investing
your money at a fixed rate of interest. This pro-
gram can simulate up to five years of playing
the market in computer time and all your data
can be stored on tape for future reference.
Although this program isn’t intended to
simulate actual market conditions, it comes
darned close.

The Investor’s Paradise package lets you ex-
perience all the thrills and triumphs of the stock
market without risking a dime.

Order No. 0125R $9.95

*A trademark of Tandy Corporation

TO ORDER: Look for these programs at
the dealer nearest you (see list of
dealers on page 205). If your store
doesn’t stock Instant Software send
your order with payment to: Instant Soft-
ware, Order Dept., Peterborough, N.H.
03458 (Add $1 .00 for handling) or call toll-
free 1 -800-258-5473 (VISA, MC and AE ac-
cepted).

Prices subject to change without notice.

Peterborough, l\I.H. 03458

t * Reader Service index— page 241

Microcomputing , October 1980 21

The TRS-80’s Color Computer , Model III and Pocket Computer.

Lancaster, PA 17604. Reader Service number
480.

Three New Computers
From Radio Shack

Radio Shack, 1800 One Tandy Center, Fort
Worth, TX 76102, recently unveiled three new
TRS-80 computers: Model III, Pocket Com-
puter and Color Computer.

The TRS-80 Model III desktop computer is
designed for more data storage, greater versa-
tility and higher computing speed. It is housed
in a single cabinet that includes a 65-key key-
board, 12-inch high-resolution video monitor,
power supply and space for up to two built-in
double-density disk drives. Available in several
configurations, it is priced from $699 for the 4K
version and is expandable to 32K with 313K of
disk storage for $2495. Model III BASIC is
compatible with most Model I programs.

The TRS-80 Pocket Computer features a
large 24-character LCD display with English
language prompting and BASIC program-
ming. It includes 1 .9K RAM that retains infor-
mation for the 300-hour life of its internal bat-
teries. The six-ounce, seven-inch-long pocket
computer can be used as a calculator to edit,
store, review and place numbers in mathemati-
cal equations with up to 15 levels of parenthe-
ses. Tapes can be loaded with an optional cas-
sette interface and may also be used to store
programs and data. Price is $249.95.

The Color Computer features high-resolu-
tion color graphics using any home color TV as
a video monitor and instant-load Program
Paks. It has a 53-key typewriter-type keyboard,
a screen format of 16 lines, 32 characters per
line, graphics array from 32 x 64 to 196 x 256,
1500 baud cassette interface and RS-232-type
serial interface. In addition to using the plug-in
Program Paks, you can program the computer
in BASIC and control the color graphics,
sound, data manipulation and storage. User
programs and data may be stored on an option-
al cassette recorder. Utilizing its built-in RS-

232C serial interface, it can serve as a TRS-80
Videotex terminal with optional software and
modem. The 4K RAM, 8K ROM version sells
for under $400. Reader Service number 482.

TRS-80 Lowercase Modification

The TRS-80 lowercase hardware modifica-
tion from Integrated Service Systems, Inc.,
101 1 West Broadway, Minneapolis, MN 5541 1 ,
includes a printed circuit board that connects to
the CPU board through a ribbon cable and sev-
eral wires. You have to remove a 2102 video
RAM and install a socket in its place for the rib-
bon cable. This is not for the novice in soldering
iron techniques. It is very easy to lift an etch by
applying too much heat. I suggest having a pro-
fessional do the installation, unless you are ex-
perienced with the tools of the trade. The in-
structions for installation come in a step-by-
step format and are easy to follow.

The modification allows 32 additional
graphics characters and an indicator in the low-
ercase mode. Lowercase characters feature
pseudo descenders. The modification comes
with software drivers on cassette in 4K, 16K,
32K and 48K format. The cassette I received
had a bad 16K dump, so I had to use the 4K to
look at the operation of the mod. The drivers
were single dumped on only one side of the
tape. I would like to see at least one set of driv-
ers dumped on each side of the tape to give you
a second chance if one of the dumps is bad.

The driver to activate the mod is unique. I
tried the mod with several other drivers (one
was called a universal driver) without finding
any compatibility. You have to use the supplied
driver, which will have to be incorporated into
any word-processing software you buy for your
system. The professionally constructed hard-
ware modification is one of the cleanest I have
seen. However, I wish the mod worked with a
more universal type of driver. Price is $41.95.
Reader Service number 475.

Edward Umlor
Fitzwilliam, NH

The Gimix two-port and eight-port serial I/O
boards.

6800/6809 I/O Boards

The Gimix 2 Port Serial I/O board has two
independent RS-232-compatible I/O ports,
with handshaking, on a single 30-pin board. It
features jumper-programmable connector
pinouts for easy cabling, independent baud rate
and interrupt jumpers for each port and the
6850 ACI A. The board is compatible with both
the SS-50 (four addresses per I/O slot) and SS-
50C (16 addresses per slot) bus configurations.
Price is $128.43.

The Gimix 8 Port board features eight in-
dependent RS-232-compatible I/O ports on a
single 50-pin board. It includes DIP-switch
selectable baud rates for each port, extended
address decoding for the SS-50C bus, selectable
interrupts and the 6850 AC1A. The board is
available with an onboard baud rate generator
for baud rates up to 38. 4K baud. Price is about
$300.

Gimix, Inc., 1337 West 37th Place, Chicago,
IL 60609. Reader Service number 481.

Digital Music Synthesizer

MusicSystem is a 16-voice digital synthesizer
that permits the creation of the sounds of real
musical instruments for the Apple 11. The gen-
eration of sounds is accomplished through fully
programmable waveforms, envelopes and am-

22 Microcomputing, October 1980

Mountain Computer’s MusicSystem.

plitudes for each musical “voice.”

Provided with the hardware system is soft-
ware for editing and playing musical composi-
tions. The Editor program permits graphical
input of sheet music utilizing standard music
notation. The player program permits poly-
phonic performance of musical compositions.
Stereo output is possible through the stereo am-
plifier and speakers or directly off the card with
stereo headphones. Price is $545.

Mountain Computer, Inc. (formerly Moun-
tain Hardware), 300 Harvey West Blvd., Santa
Cruz, CA 95060. Reader Service number 477.

132/80 Column Printer

The MS-204 is a bidirectional, 9x7 dot
matrix printer that accommodates 40, 66, 80 or
132 characters per line. It features a print head
life of 100 million characters, a 125 cps print
speed and a throughput print speed of 63 1pm.
The adjustable sprocket feed mechanism al-
lows use of forms from 2.5 to 9.5 inches wide,
with loading from either the bottom or rear. A
full 96 ASCII set permits printing upper and
lowercase characters that can be expanded for
double width fonts in boldface. The VFU (ver-
tical format unit) provides pre-programmed/
programmable tab positions, top of form and
bottom of form.

The MS-204 is compatible with TRS-80, Ap-
ple, PET, Sorcerer or any other Centronics-
type system. Price is $795.

Matchless Systems, Dept. 7, 18444 South
Broadway, Gardena, CA 90248. Reader Ser-
vice number 479.

Matchless Systems’ 132/80 column printer.

Anadex Line Printer

The DP-9500 is a dot-matrix line printer with
one of the nicest executed designs I have seen.
The unit is light and easy to carry from one set-
up to another. It features built-in parallel, serial
and current loop interfaces, as well as two type
fonts (9x9 and 7x9) for 10, 12 or 13.3 charac-
ters per inch and six or eight lines per inch.
Double width format is also available in both
fonts. Speed ranges from 150 cps to 200 cps, de-
pending on the type selected. Graphics are indi-
vidual dot addressable in a 7 x 1 format. All pa-
rameters (except I/O format) are software se-
lectable, as well as switch selectable. The
printer will handle edge-punched paper from
1.75 to 16.875 inches.

It takes only a few minutes to unpack and set
up this printer. Since it was already selected for
parallel (Centronics-format) operation, the

Braille Translator

The DS Micro Translator is a microcomput-
er-based, word -processing and braille-translat-
ing system designed for use by schools, univer-
sities, agencies and businesses that serve and/or
employ blind persons. The system provides for
both automatic translation of text to braille and
conventional, general office word-processing
tasks. The system permits a sighted person with
no knowledge of Standard English Braille,
which is a complex, semiphonetic code, to enter
and edit material from newsletters, memos and
class notes to full-length books. Entered text is
automatically translated and either formatted

The DP -9500 Line Printer from Anadex.

printer was hooked up to a TRS-80 word-pro-
cessing system. The printer performed correctly
the first time out. The ready line holds data
from going to the printer prematurely, so that
all characters were present.

The print quality in both fonts is crisp and
clear. A lever, with detent stops, at the left side
of the carriage controls the distance of the print
head from the platen. Just set the lever for max-
imum separation to load the paper more easily,
and then set it back for the correct impact pres-
sure. This is a much better arrangement than
the fixed gap method used by most printers.

The operation was flawless, except for incor-
rect perforation skip on each new page. This
might have been caused by paper drag as the
paper came out of its box. When I adjusted the
skip setting from one inch to half an inch, there
wasn’t any paging problem.

I recommend this printer as an excellent ad-
dition to any system. It is fast, clean and com-
patible with any system currently on the mar-
ket.

Anadex, Inc., 9825 De Soto Ave., Chats-
worth, CA 91311. Reader Service number 476.

Edward Umlor
Fitzwilliam, NH

by the computer to produce high-quality braille
copies of the material or formatted without
translation for equivalent print copies. The
micro translator renders text into braille at the
rate of more than 300 characters per second.

For further information, contact Duxbury
Systems, 56 Main St., Maynard, MA, 01754.
Reader Service number 489.

Z-80 Data Base Management System

Target /80 is a data base management system
for Z-80 microcomputers from Condor Com-

NEW SOFTWARE

Microcomputing , October 1980 23

JijrHr

WMM

r:*i S :T.i L-

APF’s Space Destroyer for the Imagination
Machine.

puter Corporation, 3989 Research Park Drive,
Ann Arbor, MI 48104. It contains many of the
features of Condor’s DBM-I and is designed
for transaction processing applications. Ap-
plications, developed using a nontechnical
command language, can be created for person-
nel, accounting, inventory or other business
reporting requirements. The new version uses
19 commands, including relational operations
for selecting, sorting, appending or posting
data. Target/80 is compatible with most Z-80
microcomputers with at least 48K RAM run-
ning under CP/M operating systems. Price is
under $700. Reader Service number 494.

General Ledger System

GL, a general ledger program for the
TRSDOS 1.2 on the TRS-80 Model-II, pro-
vides immediate financial information for your
company by keeping a record of all financial
transactions. Features include double entry ac-
counting, ISAM and a full 80-column screen
display. It is flexible, interactive, menu-driven
and provides automatic integration with A/P,
A/R and payroll programs. It requires a
132-column printer, a dual disk system and 64K
memory. The $129 price includes a reference
manual, an installation guide, 15 programs and
sample data files on an eight-inch diskette.

Micro Architect, Inc., 96 Dothan St., Arling-
ton, MA 02174. Reader Service number 488.

Loan Analysis Software

Personal Loan Analysis is a new software
package for the Atari 400 and 800 systems that
consists of five menu-selected programs:

Loan Repay — allows the comparison of dif-
ferent interest rates, payment periods and pres-
ent values.

Number of Time Periods — computes the time
required to pay back a loan given a set monthly
payment amount and a fixed interest rate.

Fresent Value— computes the amount of a loan
available if the consumer knows his maximum
monthly payment.

Amortization — computes all pertinent data for
the repayment of a loan.

Add -on/ Annual Percentage Rate Conversions
— converts the add-on rate to the annual per-
centage rate or the annual percentage rate to the
add-on. Cassette price is under $15.

Zapata Microsystems, PO Box 401483, Gar-
land, TX 75040. Reader Service number 493.

Video Space Game

Space Destroyer is a new cassette video space
game for the Imagination Machine from APF
Electronics, Inc., 444 Madison Ave., New
York, NY 10022. It tests your commandeering
skills to maneuver a squadron of three space
destroyers against a continuous wall of phasor-
firing aliens. One or two players may enter the
battlefield. Points are awarded and displayed
on the screen. Sound effects heighten the action
of the contest. Price is $19.95. Reader Service
number 495.

CP/M Software Guide

The CP/M Software Summary Guide , a list
of major software used on most CP/M sys-
tems, includes summaries of the CP/M
operating system, Microsoft BASIC, CBASIC
and the CP/M utilities DESPOOL, MAC and
TEX. Commands and utilities are explained
briefly with examples. This 60-page booklet
organizes features alphabetically, so you can
find an explanation quickly rather than page
through various function sections. Price is
$3.75.

Rainbow Associates, PO Box 35, Glaston-
bury, CT 06025. Reader Service number 491.

Basic-Aid for CP/M

Basic- Aid, for programmers who work with
Microsoft BASIC, allows one or two key en-
tries of over 40 BASIC statements and com-
mands. It also has nine user-definable buffers
for frequently used code (two with 64
characters and seven with 16 characters). It in-
cludes a configuration program that allows it to
be placed anywhere in memory. The program
will run on any 8080 or Z-80 CP/M system and
is available on Micropolis five-inch and stan-
dard eight -inch disks.

Mendocino Software, PO Box 1564, Willits,
CA 95490. Reader Service number 492.

Star Trac BASIC Monitor

The Star Trac extension to North Star
BASIC 5.1 offers the first fully interactive
debug monitor for any microcomputer BASIC.
It allows you to insert a breakpoint in the
BASIC program and assume full keyboard

control over subsequent execution. The most
powerful feature of Star Trac is its ability to
assert a conditional breakpoint, which allows
control over a BASIC program to be assumed
when a specified program symptom occurs,
such as when the value of a variable is altered.
This monitor allows complete control over the
BASIC program without any modification to
the program itself. Price is under $100.

Allen Ashley, 395 Sierra Madre Villa,
Pasadena, CA 91107. Reader Service number
497.

Dental Accounting System

Now your office computer can handle com-
plete dental billing with Micro Dent, a dental
billing system that will automate your billing
procedure, improve turnaround of insurance
form processing and provide mail-list and in-
formation processing for your patient records.
This program keeps track of services rendered,
bills patients and/or insurance organizations,
handles insurance pre-authorization and pre-
pares statements. It handles insurance form
types, or you can easily modify the formats that
are used in the system if new forms are added or
existing forms are altered.

You can sort through patient information
and prepare a mailing list using 15 sort criteria
keys. With a form letter merge utility, you can
send personalized form letters, dunning mes-
sages or notices to selected patients. Micro Dent
(under $1000) is available in most popular disk
formats for CP/M-based systems.

Micro DaSys, PO Box 36275, Los Angeles,
CA 90036. Reader Service number 487.

Apple II File Management System

Filemaster II is a file management system for
storing, classifying, manipulating and retriev-
ing data in the Apple II microcomputer. The
system includes four Applesoft programs — File
Designer, Search and Retrieval, Sort Informa-
tion and File Converter. Program features in-
clude computed numeric fields from user-
entered formulas, provisions for creating a sub-

MicroDaSys * dental billing system.

24 Microcomputing, October 1980

Announcing
“Hellfire
Warrior”

“Hellfire Warrior.” Really not for everybody: newcomers to
Dunjonquest should begin with something easier. Here the
monsters are deadlier, the labyrinths more difficult, the levels
far more challenging...

But for the experienced Dunjonquest game player there are more
command options, more potions (131), more magical items (including —
at last — magical armor), more special effects, more surprises. And an
innkeeper, an armorer, apothecary and magic shops.

ft a ■ • In part a sequel to The Temple of Apshai. up until now the greatest

of all the Dunjonquest games. Hellfire Warrior can also be played

completely on its own.

new Dunjonquest
computer game...
that’s really
not for
everybody:
Beginners
are likely to
be gobbled up
in the first
room. ..and
there are over
200 rooms on
four levels

Now the character you've created, re-
presenting the highest level of role-
playing to date, can explore the four
new lower levels:

Level 5— "The Lower Reaches
of Apshai." With the giant in-
sects and other nasties that swarmed through the
upper levels of Apshai. With rooms your hero can
get into, but not out of.

Level 6— "The Labyrinth." The only exit is hidden
within the Labyrinth. And' man-eating monsters can thwart
your hero.

Level 7— "The Vault of the Dead."... And of the
undead — skeletons, ghouls, mummies, specters...
invisible ghosts — lurking in the rooms, doors, secret
passages, ready to reduce your hero to a pale shadow of
himself. Permanently.

Level 8— "The plains of Hell." In an Underworld of
lost souls and shades of dead, of dragons and fiery
hounds, of bottomless pits and blasts of hellfire. our
hero must rescue the beautiful warrior maiden lying
in enchanted sleep within a wall of fire. And bring
her past unbelievable dangers and monsters . . .
even Death itself... to sun and air and life
itself.

Hellfire Warrior. The most exciting game yet
from Automated Simulations, the leading producer of
computer fantasy games.

Guaranteed: If it’s not the most exciting computer
game you’ve played, return it within ten days for a
complete refund.

Available on disk for the Apple II and Radio
Shack’s TRS80. or on cassette for the TRS80
and for the Commodore PET. The cassette:

$24.95; the disk: $29.95. Complete with a
magnificent instruction manual. Some of
the drawings in the manual are reproduced
here (in greatly reduced scale).

Use the handy coupon or, if you wish to order by MasterCard or VISA, use our toll-free
phones: In the United States: operator 861 (800) 824-7888: In California: operator
861 (800) 852-7777; In Hawaii and Alaska: operator 861 (800) 824-7919.

AUTOMATED SIMULATIONS, INC.

P.O. Box 4247, Dept. DH2
Mountain View, CA 94040 ^55

□ Yes, I want Hellfire Warrior. On a satisfaction-guaranteed/
full-money-back policy. Please send me the Hellfire Warrior on:

Disk for TRS-80 (32K. TRSDOS) @ $29.95 $

Disk for Apple (48K with Applesoft in

ROM) @ $29.95

Cassette for TRS-80 (16K. Level II)

@ $24.95

Cassette for Commodore PET (32K. old or

new ROMS) @ $24.95 ——————

Sub Total :?

Plus shipping & handling $1.00 each

•Plus sales tax for California residents

TOTAL $

□ I enclose my check in the amount of i

□ Please charge to my □ VISA or □ MasterCard account

My card no. Expires

Signature

Name

Address

City/State/Zip

’California residents: please add 6% or 672% sales tax as required.

□ Please send me your complete catalogue of computer and board fantasy games.

v* Reader Service index— page 241

Microcomputing, October 1980 25

file onto a second disk and retrieval of both ac-
tive and nonactive records, as well as special in-
put routines and error trapping. It requires
48K, Applesoft ROM and a disk drive. Price is
under $100.

Rainbow Computing, Inc., Garden Plaza
Shopping Center, 9719 Reseda Blvd., North-
ridge, CA 91324. Reader Service number 4%.

TRS-80 Assembly-Language
Development Package

Racet Computes, 702 Palmdale, Orange, CA
92665, has recently released an extended
development package for Model II assembly-
language programmers. The package includes
the following programs:

Macasm— an editor/assembler that includes
macro conditional assembly capabilities, in-
memory compiles and debug facilities. Source
programs can be saved on disk and subsequent-
ly reloaded into memory. A range of lines can
also be loaded or saved.

Szap — provides the capability to read and
modify any sector on a diskette and provides a
generalized facility for copying any number of
sectors from one area (or disk) to another.
Dis2— a system for the disassembly of Z-80
machine-language code, which can be from
memory or from a standard DOS load module
from disk. Price is $125. Reader Service
number 485.

ESP Lab

Reviewed by Eric Maloney ,

Microcomputing staff

It was only a matter of time before someone
came out with a computer program to test
extrasensory perception. But while Manhattan
Software, Inc. (PO Box 5200, Grand Central
Station, New York, NY 10017), claims that ESP
Lab is designed for “serious research,” the
program will have to undergo some careful
scrutiny before it can be accepted as a legiti-
mate tool for scientific study.

ESP researchers have spent years trying to
establish the credibility of their work. While
they have an endless supply of anecdotal evi-
dence that we humans have extrasensory pow-
ers, proving it in the lab has been another story.
Trying to isolate and identify ESP to the
satisfaction of the scientific community is like
trying to catch smoke rings with a butterfly net .
A computer only adds another variable to be
accounted for.

ESP Lab ($9.95; for the 16K TRS-80, Level
II) tests for three types of ESP— telepathy,
clairvoyance and precognition— and for
telekinesis. Except for the telepathy test, the
program can be used by two people— a tester
and a respondent — or alone.

The ESP tests are based on the experiments
of Dr. J. B. Rhine, whose work at Duke
University was instrumental in making ESP the
popular subject it is today. Rhine’s experiments
were done largely with a deck of 25 cards, each

marked with a symbol. The deck included five
each of squares, circles, triangles, ovals and
double-wavy lines.

ESP Lab simply substitutes the computer for
the cards. In the telepathy test, the computer
randomly selects a symbol, and the keyboard
operator tries to mentally project an image of
the symbol to another person. In the clairvoy-
ance experiment, the computer selects a symbol
and presents a question mark; the tester or re-
spondent enters the guess. In the precognition
test, the respondent tries to guess what symbol
the computer is going to select. In all three
cases, after 25 symbols, the computer displays
the guesses and correct answers.

Several problems become immediately evi-
dent. To begin with, while the program is based
on the Rhine cards, the symbols are actually ab-
stractions generated inside the computer. The
respondent thus has no physical object to focus
on. This may or may not be important to some-
one with extrasensory abilities, but has to be a
consideration for the serious experimenter.

Also, if the experimenter is self-testing, the
tendency is to guess the keys that represent the
symbols, rather than the symbols themselves.
Again, this may not be critical, but researchers

CLAIRVOYANCE

TRIALS

SUBJECT: ERIC MALONEY

DATE: 7/14/80

TRIAL # 1

SYMBOL

RESPONSE

1

CROSS

TRIANG

2

LINES

SQUARE

3

LINES

SQUARE

4

OVAL

LINES

5

CROSS

OVAL

6

CROSS

LINES

7

SQUARE

TRIANG

8

TRIANG

CROSS

* 9

CROSS

CROSS

* 10

CROSS

CROSS

11

CROSS

OVAL

12

TRIANG

LINES

* 13

SQUARE

SQUARE

* 14

SQUARE

SQUARE

15

LINES

TRIANG

16

TRIANG

LINES

17

LINES

SQUARE

18

OVAL

TRIANG

19

SQUARE

TRIANG

20

SQUARE

LINES

21

CROSS

OVAL

* 22

SQUARE

SQUARE

23

TRIANG

SQUARE

24

CROSS

LINES

25

CROSS

SQUARE

CORRECT RESPONSES: 5

PRECOGNITION

SCORE : 7

POSTCOGNITION SCORE: 6

Sample run 1. The program lists the sym-

bols selected by the computer, and the sub-

ject ’s responses. The precognition and post-

cognition scores indicate the number of

times the receiver correctly guesses the pre-

vious or next symbol.

can’t dismiss the possibility that it may in-
fluence test results.

The telekinesis test is better suited to com-
puter use. A box with a dot in the middle ap-
pears on the screen. The user indicates whether
he will try to mentally influence the dot to go
left or right. Eventually, the dot moves to one
side or the other. If the dot moves to the in-
dicated side more than half of the time, this is
possible evidence of telekinesis.

No matter what the test, the serious student
is faced with major questions concerning the in-
fluence the computer has on the results. It is im-
possible to say whether electrical energy has an
effect on telepathic abilities. Some scientists
have hypothesized that telepathy might actually
be carried on electromagnetic waves. And any-
one living near high-tension lines can testify to
the deadly impact electricity can have on plant
and animal life.

From here, we get into even more esoteric
questions. Might some people be more compat-
ible with computers than others, and thus be
better receivers? Could some computers be bet-
ter transmitters than others? Can a computer
have ESP?

Most of these questions will concern the seri-
ous experimenter only. For others, ESP Lab
has a variety of useful applications. For exam-
ple, it is ideal for the psychology or math stu-
dent studying probability and statistics, and
makes a perfect demonstrator for a class in-
vestigating ESP and the mind. In both cases,
students can run through the tests quickly and
easily, and can get printouts for permanent
records or future analysis.

This program is also good for the curious in-
dividual who simply wants to make an informal
study of the subject. A casual investigation can
often be more productive than one conducted
in a more formal setting.

Finally, ESP Lab is an excellent party game.
It has the appeal of keno or roulette — no mat-
ter whether you believe in ESP or chance, there
is always the urge to try beating the odds.

By the way, you can test yourself for teleki-
nesis without this program. Using your mental
powers, try turning your computer off.

Reader service number 499.

TRIAL RESULTS SUMMARY

#

CORR.

PRECOG POSTCOG

1

5

7

6

2

2

5

3

3

2

6

3

4

9

6

4

5

4

4

8

6

7

4

4

7

3

3

3

8

4

8

6

9

3

4

4

10

6

5

6

AV.

CORR.

RESPONSES:

4.50

AV.

PRECOG SCORE:

5.20

AV.

POSTCOG SCORE:

4.70

Sample run 2.

Trial results summary. A

score of 5 is considered average.

26 Microcomputing, October 1980

LETTERS TO THE EDITOR

Teachers and Computers

As noted in your June issue of Kilobaud Mi-
crocomputing , the area of investigating the
possibilities and potentials of microcomputers
in the classroom is still “virgin,” in that the in-
dustry hasn’t sincerely begun to address the as-
pect of microcomputers as instructional tools.
Granted, there is an abundant source of soft-
ware for drills and practice. For public school
systems, this may be sufficient in itself, if only
to relieve the strains of a high student -to-t each -
er ratio. In our school, with a low (15:1) ratio,
such drills are considered superficial to the
learning process. A nucleus of parents and
faculty has just formed to investigate the
possibilities and potentials of microcomputers
in the classroom.

While a handful of parents recognize the im-
portance of introducing human-to -processor
communication to our children at as early an
age as possible, we’re constantly confronted
with the question of how we should implement
the processor into the curriculum as an instruc-
tional tool. Specifically, we envision utilizing
the computer(s) for an introductory course in
programming (primary unit). An area of appli-
cation, sidestepped too long, is simulation. We
would like to see the computer used to reinforce
the learning process through automated prob-
lem analysis or trend analysis based on vari-
ables that are input.

We are now at the point where we (faculty
and parents) would like to touch bases with in-
dividuals who have successfully gone this route.
If those in the field of education or the micro-
computer industry can supply us with concrete,
logical steps toward implementation of such a
program, it would be sincerely appreciated.

Art Lane
78 Whitney Dr.
Meriden, CT 06450

William Murdoch
60 Schooner Lane
Meriden, CT 06450

Counting 0,1,2. . .

In “Questions and Answers on Memory De-
vices’’ (July 1980, p. 164), the author has done
a disservice to novice computerists with his
answer, “. . .just because,’’ referring to a ques-
tion about track 0.

As a legitimate question, it deserves a similar
answer. Zero is the track’s identifying number,
not a track count. Computerists, like everyone,
count the first item as one; however, that item’s
“name’’ is often zero for a good reason. In any

number system, using 0 to identify an item al-
lows you to distinguish, with a single digit, a
number of items equal to the base (ten items for
decimal, 16 for hexadecimal, eight for octal).
Ignoring 0 requires the use of a second digit,
hence, more memory, to identify the same
number of items.

Granted, with 77 tracks, this point is ob-
scure; however, the consistent application of
this convention leads to some degree of memo-
ry conservation.

P. V. Piescik
Wethersfield, CT

Mr. Piescik’s point is well taken. Nonethe-
less, I don’t think many people use the zero
numbering convention for the sake of conserv-
ing memory. In most cases, either approach
will work equally well. (Referencing 77 tracks
on a floppy disk, for instance, will require
seven bits, regardless of whether the first track
is 0 or 1 .)

Although my original answer may have
seemed flippant, it is essentially correct. The
zero numbering convention is simply an estab-
lished design practice that novices might as well
go along with.

David Price
Midlothian, VA

A Better Terminal

Frank Derfler’s OSI C1P terminal program
(“Dial-up Directory,’’ July 1980, p. 68) is most
interesting and useful. Regarding the RS-232C
information, the signal voltages are allowed to
be between ± 5 and ± 25 V dc. Positive voltage
is a logic 0 on the data lines and a logic 1 on the
control lines. The need for an external TTL-to-
RS-232C interface circuit between the OSI out-
put and the modem input is made unnecessary
by cutting the trace identified as W 10 on the foil
side of the board. A negative 5 volts is then con-
nected to J3, pin 7 (and not to the modem).
This will allow positive and negative voltage
swings as required by the RS-232C definition.

John G. Ruff
Minnetonka, MN

SWTP Is No Fun

Why doesn’t anyone make any “fun” soft-
ware for the SWTP 6800? Business programs,
operating systems, file sorting and manage-
ment and letter addressing are available for us
home types with small systems, but we’re not
all serious, you know.

Those TRS-80, Apple and PET guys have all

the fun with Chess, Adventures, Flight Simula-
tion and Interlude. There is nothing available
for the SWTP in this vein, except some old TSC
programs that are quite simplistic by today’s
standards. In any event, a very finite number of
these are extant, with nothing new in sight.
Now that our beloved SWTP has all but aban-
doned us to their fancy 6809 system, we are
adrift in space.

Not that I would trade my 6800 for anything
on the market. 1 like to be able to open the cage
to view boards that even an idiot would under-
stand. I like the 6800’s easy-to-use instruction
set. My primary interest is hardware, and the
SWTP is great for those of us who want to
build special boards and otherwise tinker.

More of us SWTP types should write to
thank Kilobaud Microcomputing for their sup-
port. Listen, SWTPers, if Microcomputing
stops supporting us because they think we don’t
care, all we’ll have is either a specialty newslet-
ter that thinks that everyone has a disk system
with gigabytes of memory and otherwise pub-
lishes gossip or all those pretty, colorful, com-
mercial magazines like you-know-who. And
what about the Gimix and Smoke Signal types?
Are they only interested in file sorting and man-
agement? Wouldn’t they also like to play
games, even just a little?

Lest all the other types smirk, the handwrit-
ing is on the wall. TRS-80 Level 1 is soon going
to be in the same boat. Let them try a turn at the
bailing bucket.

John Tavares

San Jose, CA

Pay Now or Pay Later

John A. Bryant’s article and program are
well-written (“Calculating Interest Rates,”
July 1980, p. 134). However, I believe there is a
flaw in the program, because it doesn’t output
the correct interest rates.

If I borrow $1000 from the bank at six per-
cent for one year, the interest is $60. My
monthly payment is $1060/12, or $88.33. If I
enter this data in the program (principal,
$1000; monthly payment, $88.33; and term of
one year), the computer says the interest rate is
10.89 percent.

Ken Walters
Red Ash, VA

It does look like six percent, Ken, and, in
fact, when I was a young fellow it was called a
six percent loan. The Truth in Lending Act
changed that and requires that the annual per-
centage rate (APR) be given on a loan. In your
example, the APR is 10.89 percent, just as the
computer said. The loan would have been a six

Microcomputing, October 1980 27

percent loan if there were no monthly payments
and you simply paid back a lump sum of $1060
a year after borrowing $1000. But when you
pay it back in monthly installments, you don’t
have the use of the entire sum for the full year,
so the effective interest rate is higher. Thanks
for your compliments on the program and arti-
cle; I probably should have explained APR.

John A. Bryant
Holcomb, NY

Shopping Around

I am a professional writer who is keenly and
sincerely interested in buying a word-process-
ing system. After reading many books and
magazines on the subject to attain a smattering
of understanding of the possibilities of what’s
out there in the market, I stuffed my check-
book into my pocket and eagerly set out to buy.
Two months later, after visiting a dozen or so
computer stores in Toronto and Buffalo, I still
haven’t bought a system, simply because no-
body will take the trouble to sell me one.

It is my finding that the staff and owners of
computer stores come in two types. Type one
sneeringly bedazzles the tyro shopper with an
incomprehensible jargon of “forty-eight -kay-
bus-byte-zed-eighty-menu-interface-vabna-
graph!” Type two asks “Whadaya mean, word
processing? Wanna see the video games? And
it’ll do your income tax really neat!”

I respectively ask owners of computer stores
to look a little more closely at the way in which
their sales staff responds to customers to ensure
that their staffs acknowledge that a good deal
of would-be buyers drift out the door from lack
of adequate service. Finally, ask your sales staff
to try a little harder than a perfunctory “You’ll
need that blue box over there and that black
dingus there, and the rest’s in this manual.”
Anybody want to sell me a word-processing
computer? Please?

Sidney Allinson
24 Ravencliff Crescent
Scarborough, Ontario
Canada

It ’s little wonder that some computer stores
are having difficulty. How many potential
users have been turned off to micros because
of treatment like you received? How many
sales have been lost? — Editors.

Computers on the Air

Aficionados of 6502 microprocessor person-
al computers have new ways to exchange com-
ments and information. Three new radio nets
on amateur radio frequencies have been an-
nounced.

An East Coast Apple Net now operates on
Saturday mornings at 1300 GMT (9 am, East-
ern Daylight Savings Time) on or near 7260
kHz. Transmission mode for this 40 meter net
is lower sideband, with W1UKZ in Scituate,
MA, as net control.

In the greater Boston area, there is a new 2

Industrial quality components
for S-100 system builders, from
California Computer Systems.

2422 Disk Controller. Single ^ double

density controller for up to four 5*4" or 8”
single-sided drives, or two double-sided drives.
Shipped with CP/M 2.0, the controller reads
and writes IBM-standard single density.
Automatically determines disk density—
single or double. Supports PerSci auto eject,
plus fast-seek for voice coil systems.

2810 Z80 CPU Board. Capable CPU for S-100
Systems operates at 2 or 4MHz, is fully Altair/
Imsai compatible. Z-80 monitor is available
separately. Includes auto addressing to
4K boundaries, plus a serial port for serial
devices, including terminals and printers.
Supports both front-panel operation and
power-on memory jump, plus wait-state gen-
eration for slower memories. Compatible with
proposed IEEE S-100 standards.

meter net, on the Norwell repeater (144.65/
145.25 MHz) for those interested in Apple
computers. W1UKZ, WA1ZKB and others act
as net control. This net is called to order at 8 pm
local time, Wednesday evenings.

A new Atari International Computer Net
now meets at 0100 GMT, Tuesdays (9 pm
EDST, Monday evenings) on 20 meters. Look
for this net on upper sideband around 14.329
kHz. W1UKZ in Scituate, MA, acts as net con-
trol.

Aside from conversation about computers in
general and the subject computers in particular,
these nets will act as funnels for as much offi-
cial information about computer developments
as can be gleaned from the manufacturers. Pro-
gram swapping via the mails is undertaken,
with projected exchange via radio anticipated
as more and more computer owners interface
with their radio equipment.

David Allen
Scituate, MA

Designing Alphabets

Your design for a computer -readable hand-
written alphabet (“Publisher’s Remarks,”
August 1980, p. 6) is similar to a project that I
have been working on for several years. We
spent considerable time and effort developing a
new method of handwriting at an early child-
hood Montessori school (Ashdon Hall in At-
lanta, GA). As a side project, using the same
pedological techniques, I developed an alpha-
bet design that required a 12-segment LED for
electronic display, but readability is easy for the
average, untrained person. Readers who are in-
terested in this project can contact me. This
method of handwriting for computer recogni-
tion could be taught in all elementary schools as
part of teaching handwriting.

Hugh S. Hunt
12219 River Road
Potomac, MD 20854

Identifying PET ROMs

I enjoyed “A ‘Personable’ Calendar” by
G. R. Boynton (August 1980, p. 168). As he
said, it is a program just waiting for you to per-
sonalize. While some might criticize its lack of
some of the programming niceties, I very much
enjoyed the program, which did exactly what
he set out to do.

My comment does not apply specifically to
his program, but to PET programs in general.
Since CBM has chosen to have a few different
ROM sets, we have to look out for the differ-
ences, since not all PET programs will run on
all PETs. It would help us true novices (not
programmers or electronics types) if the pro-
grams were identified for their ROM sets, so we
would know whether to convert all POKE/
PEEK statements.

Gerald Key
Gahanna, OH

Good idea, Gerald. Future PET authors, take
note . —Editors.

2032A 32K Static RAM. Fast static memory
operates without wait states at a full 4MHz.
Supports full and partial bank select, for
expansion beyond 64K. Addressable in 8K
blocks at 8K boundaries. Address and data
lines are fully buffered, and there are no
DMA restrictions.

2016 16K Static RAM. Fully buffered board
features 2114 static RAMs for +5v operation.
Bank select available by bank port or bank
byte, for system expansion beyond 64 K.
Addressable in 4K blocks at 4K boundaries.
LED indicators for board selection and
bank selection. Available in 200, 300, or 450
nsec versions. All versions support 4MHz
operation with no wait states.

2200A Mainframe. Rock solid, heavy gauge
cabinet includes 12-slot, actively terminated
S-100 motherboard, fan, and power supply.
Fbwer supply features 105, 115, or 125 volt
AC input power; provides +8vDC at 20 amps,
± 16v DC at 4 amps. Available in five colors.
Includes convenient, front mounted, lighted
reset switch.

2501 A Mother Board. 12 slots, actively
terminated, with all S-100 connectors included.
Distributed power line bypass, low induc-
tance interconnect— extremely low bus noise.

Prototype Boards. Four high quality prototype
boards: Solder Tail, Extender/Terminatoi;
Wire Wrap, and Etch.

P2802AA6502 CPU. Stand-alone CPU
generates fully S-100 compatible I/O signals;
executes 6502 machine language. Operates at
2MHz; capable of DMA operation.

Available nationally.

California Computer Systems industrial
quality S-100 products are available at over
250 computer retailers. Volume customers
should contact the marketing department at
CCS.

CCS. Industrial standards.

28 Microcomputing, October 1980

4

B.

We mass-produce S-100
products to deliver industrial
quality, at industrial prices.

You systems builders who need top quality, full
featured, workhorse S-100 building blocks at the most
competitive prices now have a source. California
Computer Systems.

Industrial quality means top grade materials, com-
ponents, and assembly, plus complete testing for absolute
reliability.

Industrial quality means solid designs, a full
complement of the important features you require, and
a product line that delivers performance.

Industrial pricing comes from mass production. We
buy at the right prices, and build in quantity, using
state-of-the-art facilities and techniques. Including
complete bum-in, for full performance right off the shelf.

Our industrial point of view means you get higher
performance, greater reliability, and lower prices. If these
are features you would like to see in your S-100 system,
see things our way.

Because for serious users with serious uses for
the S-100, these are the industrial standards.

California Computer Systems

250 Caribbean Sunnyvale, CA 94086 (408) 734-5811

148

ASK FOR
OUR INSTANT
DISCOUNT!

CALL TOLL FREE

U.S.A.

1 - 800 - 521 -2764

MICHIGAN

1 - 800 - 482-8393

WRITE TO: ^

“The Stocking Source”
23995 Freeway Park Dr.
Farmington Hills, Ml
48024

Buy Only From
a “Factory Authorized
Source”

List Your

PRINTERS

Price Cost

Okidata

Microline 80

S 945 ^S00

Anadex Model
DP-8000

or DP-8000 A P . .

. ,$1095.^Sil§

Anadex Model DP-9500 Ask for

orDP-9501 $1650. Our Price

Epson Model TX-80B Ask for

Friction Feed ....$ 710. Our Price

Epson Model TX-80B
Tractor Feed & Ask for

Graftrax $ 799. Our Price

Epson Model Ask for

MX-80 $ 699. Our Price

INTERFACES

Okidata Microline 80
Tractor Feed. .$100.

Okidata Microline 80
FtS-232 Interface
with 256 Character
Buffer $200.

All above Printers —
Cable from Printer
to TRS-80 $ 35.

Epson-Serial Interface
& Cable $ 90.

Epson-IEEE 488

Interface & Cable $ 80.

Epson-Apple Plug-in
Interface &

Cable $110.

WE HAVE n
A FULL HOUSE "W — \

PRINTER STANDS

Systems
Furniture
Universal
Printer
Stand
without
top, but
with paper
basket
$ 120 .

TRANSIENT CLIPPERS

The ideal Line Voltage Transient Clipper from PDF
protects against • High Energy Voltage Transients
• On-Off Switching • Lightning Induced Transients.
Model C-120Q (Other Models Stocked) $57.50

30 Microcomputing, October 1980

PROBATE

debts

YOCJR

family

inherit A ;
TAXES

James Owens
Professor of Management
American University School of Business
Washington, D.C.

Computerized
Estate Planning

This OSI program takes the tedium out of calculating and sorting
the various options for the final settlement of your wealth.

M any people spend a lifetime building
an estate (often worth hundreds of
thousands of dollars) only to let it go to
waste at their death. They plan their lives
successfully, but do little or no planning for
the disposition of their tangible worth.
Much of the estate is thus diverted into
estate taxes, probate costs, administrative
expenses and a legion of other costs, in-
stead of being channeled efficiently — and
mainly intact — to surviving loved ones.

To avoid such problems, the responsible
person plans for the inevitable event. He ex-
amines his family’s future rationally, coolly
and in ways that maximize the net estate
actually received by intended beneficiaries.
The financial community calls this estate
planning, and anybody can handle its le-
gion of complexities and mathematical
computations with a small computer (and,
of course, a lawyer).

Estate planning is a must for all working-

age people, not just senior citizens. A
50-year-old man might suffer a sudden
heart attack anytime, or a 30-year-old
divorced mother might die in an automobile
accident. In either case, an unplanned
estate usually means hardship for sur-
vivors, for whom they worked so hard during
life. Given the obvious necessity for priority
attention to a personal last will and estate
planning, why do so many neglect such a
vital matter? Three reasons, mainly: they’re

Enter in

Variable and

Description of Variable

line

sample entry

810

Y = 1979

Base year for all data entries and calculations

820

B = 50

Wife’s age in base year

830

J = 51

Husband’s age in base year

840

Tl = 20000

“Death benefit” from husband’s retirement program

850

PL = 2000

Annual increase in the value of Tl (above)

860

YD = 1999

Estimated or assumed year of wife’s death

870

A = 150000

Life insurance (except amount in line 840 above)

880

SA = 5000

Total cash, checking accounts and savings in base year

890

SI = 1000

Estimated or assumed future annual savings

900

HV = 50000

Value of home in base year

910

P = .06

General inflation (cost of living) rate for prices

920

K = .10

Average rate of earnings (income) on invested funds

930

S4 = 500

Widow’s Social Security monthly income in base year (if she were age 60 in base year
and awarded maximum)

940

ET,E = 650,322

Wife’s monthly expenses (if husband dies in base year) in two parts: those subject to
inflation: home payment that is not

950

PR = 40000

Mortgage (principal) on home in base year

Table 1. List of data variables and sample data.

too busy with the demands of a busy life to
think about death; it is most unpleasant, if
not traumatic, to confront the issue of one’s
death and make cool, rational plans for it;
and the arithmetic involved in estate plan-
ning (calculating the projected income for
survivors, varying incomes for varying in-
surance amounts, effect of estate taxes,
etc.) is too time-consuming and com-
plicated. And yet, for many, the most
critical act they will perform— or not per-
form— in life will involve estate planning.

If you have, or have access to, a comput-
er (even a small one limited to just 4K of
RAM memory), the program described here
can easily remove the major obstacles to
your estate planning. It does all the neces-
sary calculations, evaluation of alternative
plans and financial projections, quickly
enough for the busiest executive or career-
ist.

Program Objectives

The program is designed to project any-
one’s net estate after taxes (as actually in-
herited by survivors), as well as survivors’
monthly income, including Social Security
benefits, for any assumed year of death of
that person and for any number of years fol-
lowing death. Yearly calculations include
changing home value, equity in home, sav-
ings and net worth.

The prograrfi can also quickly reveal the
minimum life insurance required for a par-
ticular person and situation and the ulti-
mate effect of inadequate or no life insur-
ance.

Finally, the program might prompt some
readers to search out and organize vital sta-
tistics about their finances and the data
necessary if they are to be in control of their
lives.

Data Required

I have kept data requirements to run the
32 Microcomputing, October 1980

program at a minimum, and they should be
easily available to the user. (I permitted the
program itself considerable complexity to
keep data entry easy and convenient.) Six-
teen data are all that need be entered into
the data lines (Table 1), and most of these
will be immediately accessible. You might
have to examine your retirement program to
determine its “death benefit” and annual in-
crease in value (for lines 840 and 850); con-
tact the Social Security Administration for
the current (base year) amount for line 930
and determine current monthly expenses to
realistically project expenses for line 940.

All other data are obvious (such as your
age) or assumed (such as projected infla-
tion rate in line 910). Enter these 16 data to
run the program. (Table 1 includes sample
data for a hypothetical, but realistic, case;
program output for this case is displayed in
Table 2.) Some of your data might be zero,
as in lines 900 and 950, if you are renting
rather than buying a residence; in many
cases, line 840 and 850 will also be zero.

The sample data used here assume the
following: a husband (age 51) and wife (age
50), with no dependent children, owning a
$50,000 home with a $40,000 mortgage at
nine percent for 30 years and a $322 month-
ly payment (excluding taxes and insurance),
husband’s death benefit value and life in-
surance total of $20,000 plus $150,000, sav-
ings of $5000 and an estimate of six percent
for inflation in future years.

Program Output

Program output (Table 2) generates two
loops: the first (or outer) loop, always start-
ing with the expression “if husband dies in,”
displays wife’s net cash received (after
taxes) and her monthly income including
any Social Security benefits for that partic-
ular year of his death from 1980 to 1999. The
second (or inner) loop, always starting with
the expression “at wife’s age,” displays the

wife’s monthly income, expenses, monthly
surplus (positive or negative), home value,
equity in home and cumulative surplus for
each year of her life after his death in the
year stipulated in the particular outer loop
year. (1999 above can easily be changed in
line 860 for more or fewer years’ projec-
tions.)

If this looks complicated, the potential
reality it represents is just that— compli-
cated. The wife’s income and. other vari-
ables change depending upon two factors:
the year of the husband’s death and (for
each year of his death) the number of years
(her age) following his death.

For example, if he dies in 1985, the base
amount of insurance, savings and so on de-
termining the next ten or 20 years of her
life’s monthly income is far different than
the base amount if he died in 1980. In the
sample data and output, the program gener-
ates 361 inner loop displays (19 inner loop
financial situations times 19 outer loop pos-
sibilities of death), and all are different de-
pending on the two factors. Fortunately, the
program incorporates and handles these
complexities, and the program user need
only enter base year data (as above) and
read the output information for each year.

To illustrate several immediate uses of
the program output (still using Table 1 sam-
ple data), suppose that the husband dies in
1980. In that year, when the wife is 51, her
monthly surplus or margin is a comfortable
$431. But by the time she is 59, just before
Social Security benefits are activated at 60,
her monthly surplus has declined to zero.
The reason is that her income is frozen at
the level of the year of the husband’s death
while inflation drives up monthly expenses
each year.

Fortunately, in this case, her cumulative
surplus from prior years is sufficient to ab-
sorb the erosion of the monthly surplus. By
contrast, if life insurance had been $100,000
instead of $150,000, the wife’s monthly sur-
plus at 59 would be - $419 and cumulative
surplus - $20,000 (obviously, the economic
system would not extend her such bor-
rowed funds, and the only option would be a
drastic collapse in her standard of living).

For anyone using this program, many as-
sumptions can quickly be entered into data
lines and run to test their long-term conse-
quences, especially assumptions about
minimum life insurance needed at any
given time.

Program Mechanics and Documentation

The program has two loops— an outer
GOTO loop and an inner FOR-NEXT loop.
The inner loop also incorporates a number
of subroutine loops. Many secondary vari-
ables (such as BB) and temporary variables
(such as VI) are used to isolate the intended
effect on one loop from the unintended ef-

feet upon the other as numerical values
need programmed changes in both— but at
different program points. Using the basic
variables in the Table 1 data list as a start-
ing point, it will be easy to trace the logic
and movement of the program.

Program documentation (REM lines) has
been eliminated and placed instead in the
text here to minimize memory required to
run the program. As listed, the program can
output 20 or more outer loops, each with 20
or more inner loops, and do it within the lim-
its of a 4K RAM memory system. Thus, any-
one, even with his first personal computer,
can use the program immediately.

Only a few other program lines need spe-
cial comment:

• Social Security benefits are initiated and
“indexed” in lines 116, 131 and 930.

• Estate taxes are calculated in line 126.

• Death benefit (line 840) is frozen at hus-
band’s retirement age in line 121.

• Monthly expenses subject to inflation are
increased by P factor in lines 133 and 177.

• Calculations for home value, amortiza-
tion of mortgage and home equity are in
lines 310 through 315.

Note that, in line with past years’ pat-
terns, the annual increases in home value
are set two percentage points above the
rate of general inflation (P), and that home
value and equity rates of increase decline
slightly in the later years of a run to reflect
some real depreciation with age. For brevi-
ty, I used different formulas to calculate
home value and equity in the outer as con-
trasted with the inner loops; this results in
slight, but insignificant, absolute value vari-
ations in the later years for each loop during
a run.

Program Modifications

My primary criteria in the program design
were convenience and ease of use. At
times, however, you will want to modify the
program itself. Mainly, there are three such
occasions.

The first concerns the estate tax formula
built into the program. Current law allows a
$250,000 marital deduction when a husband
passes his estate, at death, to his wife (pro-
vided he explicitly declares in his will his in-
tent to do so— neglect in making a will with
such an explicit statement in it disallows
the deduction and deprives the wife of
about $80,000 to taxes!).

Current law has also set the unified credit
against the actual net estate tax at $47,000,
deductible from the tax itself. Thus, if you
plan your estate properly, you can take ad-
vantage of the deduction and credit and
pass on an estate of up to $400,000 with no
estate taxes at all. But the law changes of-
ten— usually every two years with congres-
sional elections. When it does, make the
change in the program in line 126 by substi-

10 REM
28 REM

**

ESTRTE PLANNING

**

30 REM

**

**

48 REM

**

PROGRAM BY J. OWENS, PH. D. , 1979

**

50 REM

60 DEF FNT(X) = INT(X * 1 +. 5)/l
70 DEF FNH(X) = INT(X * 108 +. 5)/100

100 REfiD V, 6; J; TI; PL; YD; ft; Sft; SI; HV; P; K; S4; ET; E; PR
110 YY=Y : B8=B : T=TI : HW=HV : RP=PR : ftft=fi

115 IF B>59 THEN GOTO 120

116 S4=FNT(S4+(S4 * P * (60-B^))

120 PRINT H IF HUSBftND DIES IN"; Y+i; "WIFE WILL INHERIT CASH:"

121 Y=Y+1 : B=6+l : J=J+i : IF J<66 THEN TI=TI+PL
123 Sfi=Sft+Sl : TT=TI+fl+Sft : T9=TT+EH : X=X+1

125 PRINT" INSURANCE"^; "+ DEATH BENEFIT"; TI; "+ SAVINGS";SA; " 3 ";TT

126 IF T9M26080 THEN TX=FNT((T9-426000)* 33) : 1FT9<426000THENTX=0

128 V=TT-TX

129 IF B < 60 THEN SS=0

130 IF B>59 THEN SS=FNT(S4)

131 IF B>59 THEN S4=S4+<S4*P)

132 W=FNT((V*K)/12)

133 ET=ET+(ET*P) : EX=FNT(E+ET)

135 PRINT"NET CftSH INHERITED LESS TAXESC; TX; M ) 3 "; V

136 PRINTTABQ5); "MONTHLY INCOME 3 "; VV; "+S0C. SEC. ";SS; *="; VV+SS
140 FOR R= 1 TO (YD-(Y+D)

145 PRINT

150 PRINT"fiT WIFE'S AGE"; BB+1; "(IN"; YY+1; ")"

160 BB=BB+1 : YY=YY+i : IF B6>60 THEN GOTO 170
165 IF B8>59 THEN SS=S4

170 IN=W+SS : SS=FNT (SS+(SS*P> ) : EE=E7+E8 : IF £E>EX THEN GOTO 177

175 E?=E : E8=ET

177 EE=FNT(E7+E8) : E8=E8+(E8*P)

290 EE=FNT(E7+E8) : SU=FNT(IN-EE)

300 PRINT"HER MONTHLY INC0ME="; IN; "AND EXPENSE 3 "; EE; "< SURPLUS 3 ";SU
305 IF R=1 THEN HE=HV-PR

310 HV=HV+(HV*(P+. 02)) : V1=PR*. 09 : V2=E*12 : PR=PR-(V2-V1)

315 HE=HV-PR: REM AMORTIZING AT 9K AND BY YEAR; NOT MONTH
325 PRINTTAB(8); "HOME VALUE 3 "; FNT(HV), "HOME EQUITY 3 "; FNT(HE)

330 CS=CS+(SU*12)

350 PRINTTAB(8); "WIFE'S CUMULATIVE («0WTH-BV-f1CWTH)SLIRPLUS= H ; CS
500 NEXT R

510 EE=EX : E7=E : E8=ET
520 BB=B : YY=Y : T=TI : CS=0
522 HV=HW+(HW * «P+. 02)* X))

530 PR=RP-( ( (E*12)*X)-( (RP*. 09)*X))

600 IF Y=YD THEN END
650 PRINT
700 GOTO 120
810 DATA 1979
820 DATA 50
830 DATA 51
840 DATA 28000
850 DATA 2900
860 DATA 1999
870 DATA 150000
888 DATA 5000
890 DATA 1080
900 DATA 50000
910 DATA . 06
920 DATA . 10
930 DATA 508
940 DATA 650; 322
950 DATA 40000

Program listing. Estate Planning program in OSI BASIC.

Microcomputing, October 1980 33

tuting new numbers for the present line’s
.33 and 426000.

The second possible modification in-
volves life insurance provisions throughout
the program that cannot be handled in the
data lines. The program assumes a set

amount of life insurance (as entered in line
870) until the husband’s death. If a portion
is term or group insurance, ending at the
husband’s retirement age of 65, that
amount must be deducted by adding a new
program line. If, for example, the term

amount ending at 65 were $20,000, then
add:

Line 122 IF J= 66 THEN LET A = A- 20000

If the amount affected here were $30,000
terminating at age 62, line 122 would be-
come:

Q>

•Q

.cc

o>

.c

co

Q.

O

S

2

o>

8

a

5

2

cvi

Q>

.CO

IF HUSBAND DIES IN 1988 WIFE HILL INHERIT CASH:

INSURANCE 150088 ♦ DEATH BENEFIT 22908 + SAVINGS 6898 = 178888
NET CASH INHERITED LESS TAXES< 0 ) = 178888

MONTHLY INC0ME= 1483 ♦SOC. SEC. 0 = 1483

AT WIFE'S AGE 51 (IN I960 )

HER MONTHLY INCOME* 1483 AND EXPENSE= 1052 (SURPLUS* 431
HOPE VALUE= 54090 HOME EQUITY= 14264
WIFE'S CUMULATIVE ( M0NTH-6Y-M0NTH ) SURPLUS 5 5172

AT WIFE'S AGE 52 (IN 1981 )

HER MONTHLY IHC0ME= 1483 AND EXPENSE = 18% (SURPLUS= 387
HOME VALUE= 58328 HOME EQUITY* 18872
WIFE'S CUMULATIVE <MONTH-BY-HONTH)SURPLUS= 9816

AT WIFE'S AGE 53 (IN 1982 )

HER MONTHLY INC0ME= 1483 AND EXPENSE= 1143 (SURPLUS= 340
HOME VALUE= 62986 HOME EQUITY= 23851
WIFE'S CUMULATIVE (MONTH-BY-MONTH)SURPLUSs 13896

AT WIFE'S AGE 54 (IN 1983 )

HER MONTHLY INCOPC* 1483 AND EXPENSE= 1192 (SURPLUS= 291
HOME VALUE= 68824 HOME EGU1TY= 29232
WIFE'S CUMULATIVE ( MONTH-BY-MONTH )SURPLUS= 17388

AT WIFE'S AGE 55 (IN 1984 )

HER MONTHLY INCOME= 1483 AND EXPENSE= 1244 (SURPLUS= 239
HOME VALUES 73466 HOME EQUITY= 35846
WIFE'S CUMULATIVE (M0NTH-8V-M0NTH)SURPLUS= 28256

AT WIFE'S AGE 56 (IN 1985 )

HER MONTHLY INCOME= 1483 AND EXPENSE= 1299 (SURPLUS= 184
HOME VALUES 79344 HOME EQUITY* 41338
WIFE'S CUMULATIVE (MONTH-BY-MONTH)SURPLUS= 22464

AT WIFE'S AGE 57 (IN 1986 )

HER MONTHLY INCOME= 1483 AND EXPENSE= 1358 (SURPLUS* 125
HOME VALUE* 85691 HOME EQUITY* 48128
WIFE'S CUMULATIVE ( MONTH- BY-MONTH)SURPL US* 23964

AT WIFE'S AGE 58 (IN 1987 )

HER MONTHLY INCOME* 1483 AND EXPENSE* 1420 (SURPLUS* 63
HOME VALUE* 92547 HOME EQUITY* 55458
WIFE'S CUMULATIVE (MONTH-BY-MONTH) SURPLUS* 24728

AT WIFE'S AGE 59 (IN 1988 )

HER MONTHLY INCOME* 1483 AND EXPENSE* 1486 (SURPLUS*- 3
HOME VALUE* 99958 HOME EQUITY* 63388
WIFE'S CUMULATIVE (M0NTH-6Y-H0NTH) SURPLUS* 24684

AT WIFE'S AGE 68 (IN 1989 )

ICR MONTHLY INCOME* 2283 AND EXPENSE* 1556 (SURPLUS* 727
HOME VALUE* 187946 HOME EQUITY* 71957
WIFE'S CUMULATIVE (MONTH-BY-HONTH)SURPLUS* 33488

AT WIFE'S AGE 61 (IN 1998 )

HER MONTHLY INCOME* 2331 AND EXPENSE* 1638 (SURPLUS* 701
HOME VALUE* 116582 HOME EQUITY* 81218
WIFE'S CUMULATIVE (MONTH-BY-MONTH)SURPLUS* 41828

AT WIFE'S AGE 62 (IN 1991 )

HER MONTHLY INCOME* 2382 AND EXPENSE* 1788 (SURPLUS* 674
HOME VALUE* 125989 HOME EQUITY* 91226
WIFE'S CUMULATIVE (MONTH-BY-MONTH) SURPLUS* 49988

AT WIFE'S AGE 63 (IN 1992 )

HER MONTHLY INCOME* 2436 AND EXPENSE* 1792 (SURPLUS* 644
HOME VALUE* 135981 HOME EQUITY* 182041
WIFE'S CUMULATIVE (MONTH-BY-MONTH) SURPLUS* 57636

AT WIFE'S AGE 64 (IN 1993 )

ICR MONTHLY INCOME* 2493 AND EXPENSE* 1888 (SURPLUS* 613
HOME VALUE* 146860 HOME EQUITY* 113729
WIFE'S CUMULATIVE (HONTH-BY-HONTH)SURPLUS* 64992

AT WIFE'S AGE 65 (IN 1994 )

ICR MONTH.Y INCOME* 2554 AND EXPENSE* 1973 (SURPLUS* 581
HOME VALUE* 158688 HOPC EQUITY* 126360
WIFE'S CUMULATIVE (M0NTH-8Y-M0NTH)SURPLUS= 71964

AT WIFE'S AGE 66 (IN 1995 )

HER MONTHLY INCOME* 2618 AW) EXPENSE* 2872 (SURPLUS* 546
HOPC VALUE* 171297 HOPC EQUITY* 148818
WIFE'S CUMULATIVE (MONTH-BY-MONTH)SURPLUS* 78516

AT WIFE'S AGE 67 (IN 1996 )

ICR MONTHLY INCOME* 2686 AW) EffENSE* 2177 (SURPLUS* 589
HOME VALUE* 185881 HOC EQUITY* 154762
WIFE'S CUMULATIVE ( MONTH-BY-MONTH ) SURPLUS* 84624

AT WIFE'S AGE 68 (IN 1997 )

ICR MONTWY INCOPC* 2758 AND EXPENSE* 2289 (SURPLUS* 469
HOME VALUE* 199881 HOPC EQUITY* 178785
WIFE'S CUMULATIVE (MONTH-BY-MONTH) SURPLUS 98252

IF HUSBAND DIES IN 1995 WIFE WILL INHERIT CASH:

INSURANCE 158088 + DEATH BENEFIT 48888 ♦ SAVINGS 21808 = 219888
NET CASH INHERITED LESS TAXES< 8 ) = 219888

MONTHLY INCOME* 1825 +SOC. SEC. 1135 = 2968

AT WIFE'S AGE 66 (IN 1995 )

HER MONTHLY INCOME* 2968 AND EXPENSE* 2872 (SURPLUS* 888
HOME VALUE* 118888 HOME EQUITY* 83388
WIFE'S CUMULATIVE (MONTH-BY-MONTH ) SURPLUS* 18656

AT WIFE'S AGE 67 (IN 1996 )

HER MONTHLY INCOME* 3828 AND EXPENSE* 2177 (SURPLUS* 851
HOME VALUE* 128384 HOME EQUITY* 93561
WIFE'S CUMULATIVE (MONTH-BY-HONTH)SURPLUS* 28868

AT WIFE'S AGE 68 (IN 1997 )

HER MONTHLY INCOME* 3188 AND EXPENSE* 2289 (SURPLUS* 811
HOME VALUE* 138568 HOME EQUITY* 184562
WIFE'S CUMULATIVE (MONTH-BY-MONTH)SURPLUS* 38688

IF HUSBAND DIES IN 1996 WIFE HILL IWCRIT CASH:

INSURANCE 158008 + DEATH BENEFIT 48888 + SAVINGS 22888 = 228880
NET CASH INHERITED LESS TAXES( 8 ) = 220888

MONTHLY INCOME* 1833 +SOC. SEC. 1283 = 3836

AT WIFE'S AGE 67 (IN 1996 )

HER MONTHLY INCOME* 3836 AND EXPENSE* 2177 (SURPLUS* 859
HOME VALUE* 123128 HOME EQUITY* 87988
WIFE'S CUMULATIVE (MONTH-BY-MONTH)SURPLUS* 18388

AT WIFE'S AGE 68 (IN 1997 )

HER MONTHLY INCOME* 3188 AND EXPENSE* 2289 (SURPLUS* 819
HOME VALUE* 132978 HOPC EQUITY* 98548
WIFE'S CUMULATIVE (MONTH-BY-MONTH)SURPLUS* 28136

IF HUSBAND DIES IN 1997 WIFE WILL IWCRIT CASH:

INSURANCE 158008 ♦ DEATH BENEFIT 48888 ♦ SAVINGS 23888 = 221888
NET CASH INHERITED LESS TAXES ( 8 ) = 221888

MONTHLY INCOME* 1842 +SOC. SEC. 1275 = 3117

AT WIFE'S AGE 68 (IN 1997 )

HER MONTHLY INCOME* 3117 AW) EXPENSE* 2289 (SURPLUS* 828
HOME VALUE* 127448 HOME EQUITY* 92596
WIFE'S CUMULATIVE (MONTH-BY-MONTH)SURPLUS* 9936

IF HUSBAND DIES IN 1998 WIFE WILL INHERIT CASH:

INSURANCE 150880 + DEATH BENEFIT 48888 + SAVINGS 24888 = 222888
NET CASH INHERITED LESS TAXES( 8 ) * 222888

MONTHLY INCOME* 1858 +SOC SEC. 1352 = 3282

AT WIFE'S AGE 69 (IN 1998 )

HER MONTHLY INCOME* 3282 AND EXPENSE* 2487 (SURPLUS* 795
HOME VALUE* 131768 HOME EQUITY* 97284
WIFE'S CUMULATIVE (MONTH-BY-MONTH) SURPLUS* 9548

34 Microcomputing, October 1980

IF J =62 THEN LET A = A-30000

The third possible modification makes
the program more convenient to use. As
programmed, any output will display in se-
quence many inner loop years for each
outer loop year of the husband’s death. For
a quicker summary, outputting outer year
results only, change line 140 to: FOR R = 1
TO 1.

If you want only, say, three inner loop
years for each outer loop year, then use line
140 in the form:
for r = 1 TO 3

Conclusion

This program is no substitute for your
lawyer’s and banker’s professional advice
about your will and strategies available in
estate planning. But it makes the calcula-
tions you need to see future objective re-
sults of current decisions or options, and
helps evaluate those decisions and op-
tions.!

Dr. James Owens is the director of the
Department of Management Sciences
and a professor of management and or-
ganizational behavior at the American
University School of Business Adminis-
tration in Washington, D.C.

□ 51

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Reader Service index— page 241

Microcomputing, October 1980 35

1 "S O f ~tVu , (SQS

Conversing with
Your Computer

Businessmen, call your computer
from the nearest phone.

Marc Seligman
320 Bryn Mawr A ve.

Bala Cynwyd, PA 19004

R emote use of your computer is neither
as expensive nor as complicated as
you might believe. Follow these instruc-
tions and you will be able to tie into your
computer from a friend’s house, a business
meeting or your favorite watering hole.

This article is most useful to owners of
the Vector MZ system with the Mindless
Terminal. It can also be adapted for other
MZ systems and for computers from other
manufacturers. You must, however, design
your own conversions.

The Vector MZ has enjoyed remarkable
success throughout the country, but
especially on the West Coast. Due to its
popularity as a small-business system,
major modifications are often needed. The
trouble is, most purchasers have no
knowledge of machine coding or assembly
language, and don’t wish to learn. They
want a fast, reliable system. They are not
hobbyists, but dedicated users who need
their computers for serious business ap-
plications. When they have a problem, they
want it solved now, without a lot of foot-
shuffling and programs-take-time-to-write
excuses.

Were these users to ask about telephone
interfacing at their computer store, they
would most likely be steered to an expen-
sive and complicated internal auto-answer
modem. It they were foolish enough to buy
an auto-answer external modem with the

hope that they could just plug it in, they
would be in for a rude awakening.

Telephone Connections

This method is inexpensive and amazing-
ly effective. The necessary parts include a
Vector MZ with Mindless Terminal, a Texas
Instruments Model 745 portable data ter-
minal set to mark parity ($1595), a Data
Access Systems Model DASI 68-01 modem
($300) and an RS-232 cable (use pins 1, 2, 3,
4, 6, 7, 8 and 20; wire pin 2 of one plug to pin
3 of the other and vice versa). (See Fig. 1.)

If you don’t know anything about wiring a
cable, have the store employees wire it for
you. All wiring is direct except for the pin 2
and 3 exchange noted above.

Before you make the big test, be sure that
the printer routine on your RES module is
the DECW4 version. Section 2.2.1. 6 of your
Vector Graphic manual tells you how. If you
normally use another version, don’t panic.
Copy your master diskette, then modify the
RES module and save it according to sec-
tion 2.2.1. 6. Just copy any of your programs
onto this disk and make sure you use only
this disk when you access the computer
from your remote terminal.

You also have to adjust the baud rate of
your computer to match the speed of the
745 (300 baud). Even if you’ve never opened
up your computer, this is one time that you
should. As with all electrical appliances,
make sure it’s unplugged.

Unscrew the four Phillips-head screws
(two on each side) on the top part of the
case and lift off the top. On one of the
printed circuit boards near the rear of the

computer, a series of small switches in the
upper left corner will usually be set to 1200.
Using a pencil or small screwdriver, pop the
switch that is out of line so that it is in line
with the others. Next, find the switch la-
beled 300 and pop that out of line.

When you first open the computer, touch
your hand to the metal frame on the left side
that acts as a guide for the circuit boards,
but don’t touch anything else. Some elec-
trical wizards feel that this will ground any
loose static electricity in your body and pre-
vent the computer from having a coronary if
your hand happens to slip later on in the
procedure.

Plug the modem into the wall outlet. Con-
nect its telephone jack to the modular out-
let that you already have on the wall. If you
don’t have a modular jack, Radio Shack
sells adapters that you can plug in or screw
on to your telephone connector box. Again,
if you are mechanically inept, have the
phone company install the adapter.

If you have an extra modular cable, you
can plug your telephone into the extra
modular socket on the back of the DASI
68-01 (a nice feature that saves having to
remember to replug the telephone into the
wall when you are done with your remote
work). Finally, connect the RS-232 cable be-
tween the modem and the computer (either
side can plug into either device).

Software

Turn on the computer and bring up
BASIC. Enter the program listing and save
it. I call this program Remote. The next to
last statement loads my menu so that I am

36 Microcomputing, October 1980

ready to run as soon as the ready prompt is
flashed on the Mindless Terminal. For your
own use, enter the name of your menu pro-
gram. If you do not have a menu program,
enter the name of any other program you
have on the diskette.

Run the program. The computer will set
itself for input through the RS-232 connec-
tor rather than through the Mindless Ter-
minal. All operations can be performed by
direct wiring to the connector (as with a
Texas Instruments Model 820 KSR printer)
or remotely through a modem connected to
the computer.

Press the power button on the modem. A
red light indicates that all is fine. Go to
another phone and dial the first phone num-
ber. A ring or two will be followed by a high-
pitched sound. Following the procedures
that came with the Tl 745 instruction book,
put the phone handset into the acoustic
cuffs of the 745, which is already turned on,
according to the manual’s instructions.

Once the connection is made, press the
on-line key and make sure that the terminal
is set for full duplex and high speed (read
the manual for details). Type a control-C to
set a little interrupt; the computer will
follow on the next line with a ready. If
nothing happens, make sure that the green
carrier detect light is on, and that the ter-
minal is on-line. The switches for full duplex

and high speed will not prevent data from
being transmitted, even if they are set incor-
rectly. But then again, the data will be so
garbled that the messages will be mean-
ingless.

Operation

From your portable terminal you can do
whatever you like. The escape key on the
portable terminal will not function. A con-
trol-X will bring back the BASIC sign-on
message but will preserve whatever pro-
gram you had in memory. A rubout will
generate a back space and the ability to
change previously entered information. A
control-U will erase an entire line’s input.
Control-S will stop the computer from send-
ing more information. Hitting any other key
will resume transmission with no data loss.

With this particular arrangement, you will
receive on the 745 an echo of what the com-
puter receives. Local printing is sup-
pressed, so typing will be a little strange,
since there will be a brief delay between typ-
ing a character and having it appear on the
thermal paper.

To reuse your computer with the Mind-
less Terminal, hit the computer reset button
and type in a B from the keyboard on the
Mindless Terminal. The entire system will
reboot and allow normal operation of the
system.

To use the computer from a remote loca-
tion, make sure that the speed is set to 300
baud and execute PLOADG Remote. Test
the system with the portable terminal be-
fore you leave the computer far behind. If
you accidentally load a program other than
Remote, the portable terminal will not work,
and if you need to access your computer,
you won’t be able to do so. Also, turn off the
modem when not in use, or else people will
never be able to reach you by telephone.

The modem disconnects the computer
and hangs up the phone after you terminate
remote communication. You can call it
again and again without having to reset
anything on the computer. It is truly an effi-
cient, low-cost method of accessing your
computer from the field. ■

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

210

220

230

240

250

260

270

280

290

300

310

320

330

340

350

360

370

380

REM ** REMOTE
REM **

REM ** THIS PROGRAM SETS UP THE VECTOR MZ SYSTEM B FOR REMOTE USE THROUGH
REM ** A MODEM (DAS I 68-01) ATTACHED TO ITS RS 232 CONNECTOR. THE REMOTE
REM ** DEVICE IS A TEXAS INSTRUMENTS 745 PORTABLE DATA TERMINAL SET FOR
REM ** MARK PARITY. BAUD RATE ON THE COMPUTER MUST BE SET TO 300.

REM

REM ** WRITTEN BY: MARC SELIGMAN

REM ** SEPTEMBER 11. 1979

REM **

REM ** FOR PERSONAL USE ONLY. NOT TO BE RESOLD.

REM
REM
REM

ASSIGN (2,3)

POKE ( 1 6R07 1 2 ) = 1 6RDB
POKE ( 1 6R071 3 ) = 1 6R07
POKE ( 1 6R07 1 4 ) = 1 6REE
POKE ( 1 6R07 1 5 ) = 1 6R04
POKE ( 1 6R07 1 6 ) = 1 6RE6
POKE ( 1 6R071 7 ) = 1 6R02
POKE ( 1 6R07 1 8 ) = 1 6RC8
POKE ( 1 6R07 1 9 ) = 1 6RDB
POKE ( 1 6R07 1 A ) = 1 6R06
POKE ( 1 6R07 1 B ) = 1 6RE6
POKE( 16R071C)=16R7F
POKE ( 1 6R07 1 D ) = 1 6RFE
P0KE(16R071E)=16R18
POKE ( 1 6R07 1 F ) = 1 6RCA
POKE ( 1 6R0720 ) - 1 6R52
POKE( 16R0721 )=16RC1
POKE ( 1 6R0722 ) - 1 6RC9
POKE ( 1 6R05F9 ) = 1 6R 1 2
POKE ( 1 6R05FA ) = 1 6R07
POKE ( 1 6R0605 ) = 1 6R 1 2
POKE ( 1 6R0606 ) = 1 6R07
LOAD "MENU"

END

Program listing.

Microcomputing, October 1980 37

JPC PRODUCTS FOR

\

6800

COMPUTERS

High Performance Cassette Interface

• FAST - 4800 Baud Loads 4K in 8 Seconds!

• RELIABLE - Error Rate Less Than 1 in 10* Bytes.

• CONVENIENT - Plugs Directly Into The SWTPC.

• PLUS - A Fully Buffered 8 Bit Output Port Provided.

• LOW COST - $59.95 For Complete Kit.

• OPTIONAL - CFM/3 File Manager.

Manual 8- Listing $19.95
(For Cassette Add) $ 6.95

TERMS CASH. MC or VISA; Shipping & Handling $3 00

Order Phone (505) 294-4623
P.O. Box 5615
Albuquerque, N.M. 87185

A Quote on our new

Integrated Accounting System (IAS):

. . an excellent value — particularly good are the error checking and
data entry procedures — documentation is good (both within the
programs and separately provided materials }. "

Mr. E. Lindow

Director of Computer Operations
Metric Industries

Some of the IAS features include:

Custom Chart of Accounts limited only by available memory (a 32K
system will support up to 200 accounts including DOS and BASIC).
Financial reports (service or manufacturing) including Income State-
ment with current and Year-To-Date totals, Balance Sheet and
Worksheet. Provision for "Header" and "Subsidiary" accounts. Check
register. Account balances at any time. Up to 1100 Accounts
Receivable. AR includes read-to-mail bills, automatic aging of AR ac-
counts and posting to General Ledger. Up to 1100 Accounts Payable
with check printing. Payroll supports up to 200 employees and permits
payment by week, bi-weekly, semi-monthly, monthly, hourly or on
salary or any combination thereof. Prints paychecks and W2 forms.
Maintains all employee data with full editing. Current, quarterly and Y-
T-D employee totals. IAS includes over 30 reports and listings to give
you the information you need when you need it. Over 65 programs in
all!

Prices: General Ledger; $125.00, G.L. plus 1 subsystem; $225.00; G.L.
plus 2 subsystems; $300.00; G.L. plus AR, AP and Payroll
subsystems; $350.00. Manual for IAS is $20.00 (credited
towards purchase). Please include $3.00 for First Class
postage.

IAS requires 32K of memory, North Star Release 4 or later
DOS and BASIC and two disk drives. Printer output is
provided for, but not required. Specify video device when
82 ordering.

master charge EC0S0FT Phone orders only: (317)253-6828

p Q B(JX 68602 Indianapolis, IN 46268

September, October Super Special

Apple II 16K

$ 950 . 00 ....

INTEGRAL DATA
SYSTEMS

440G: Paper Tiger
with Graphics;

2K Buffer

460: Word

Processing Quality
460G: IDS 460 w/Graphics

DOUBLE VISION
DISK II

with controller
without controller

MICR0M0DEM

PASCAL

LEEDEX MONITOR
KG-12C

Green Phosphor

12" Screen w/Glare Cover

18 MHz bandwidth

$950

rag. $1095

Centronics 737

High Quality Dot Matrix

Apple Silentype

Includes interface and
graphic capabilities

$895

reg. 995.00

$535

reg. 595.00

$1099

reg. 1295

$1199

reg. 1395

Apple Parallel Int.
Apple Serial Int.
Centronics Parallel Int.

$160

reg. $180

$175

reg. $195

$185

reg. $225

S295.00

$525.00

$445.00

$325.00

$425.00

16K RAMS for

$i40.oo VERBATIM
$275.00 DISKS 007

10 for $£/

The Computer Stop

16919 Hawthorne Blvd.

Lawndale, CA 90260

105

MON. • SAT.

L

(213) 371-4010

10-6 A

LOW COST IMPACT PRINTER

48 Column Impact Printer available in KIT form or ASSEMBLED and
TESTED, ready to be connected to your computer. Primary features
include; Microprocessor controlled and programmable with 32 system
level software commands. 96 ASCII characters with upper and lower
case, no eye straining print with 9 software selectable sizes from 5 x 7 to
larger 10 x 7 and 10 x 14 character fonts, reverse font printing
capability, standard parallel and serial interface, baudrate selectable
from 1 10 to 9600 baud, plus many more functions at your command.

Prices for KITS are $295 (101A-48K) without enclosure and $325
(101 A-48KE) with enclosure. KITS include all electronics, mechanical
parts and detailed assembly instructions.

ASSEMBLED and TESTED Impact Printers— prices are: $325
(101A-48) excluding enclosure, $355 (101A 48E) with enclosure.

For further information, contact;

COOLSOL, INC. ^ 2 92

P.O. Box 743. Anaheim, Ca. 92805 Phone: (714) 545-2216
(7 days a week)

38 Microcomputing, October 1980

FOR APPLE II AND APPLE II PLUS COMPUTERS

DoubleVision”

80 x 24 Video Display with Upper and Lower Case

COLUMNS UNES 1 * B B

• is a hardware board that may be plugged into any slot in Apple II or Apple II Plus 32K or 48K Disks • full 128 ASCII character set, including
control characters • fully programmable cursor • built in light pen capability • inverse video • full cursor control • works with
50/60Hz • has 2k of its own screen memory • has its own video output jack that must be connected to a monitor (or a high band width black
& white TV thru a good RF modulator). Color TV’s produce a poor display and are not recommended. • permits you to connect another
monitor (or a T.V. set thru RFmod) to the Apple video output jack • displays 24 lines of 80 column text — programmable for different
values • permits you to have graphics on Apple video output • video output and Apple video output may be connected to one monitor thru
optional video switch • is active only when addressed for reading from or writing to • accepts lower case input from keyboard by use of
escape key. (no modification required) or direct use of shift key (1-wire connection from shift key pad to DoubleVision required). • is compati-
ble with the latest version of various word processing software packages. Presently these include Apple-pie 2.0— Programma International,
Easywriter Professional system— Informational Unlimited, Text Editor/Formatter— Peripheral’s Unltd. (when ordering from these companies,
please ask for versions compatible with DoubleVision). All software available from Computer Stop when released. • Peripheral’s Unltd.
B.l.T.S. and P.l.T.S. and Southeastern Software’s “DATA CAPTURE’’ with Micromodem and communication card. These packages give ability
to upload, transfer and download files from remote computers, and all at 80 columns! • Programma Int. latest assembler LISA V:20 will sup-
port full 80 column display • is transparent for use with Basic and Pascal • software on disk for easy modification and adaptation for dif-
ferent applications • completely commented source listing of software and hardware schematics available • PASCAL
(optional) • becomes the console when installed in Pascal • Permits 80 column text processing with full upper/lower case while using
Pascal’s editor • must be plugged into slot 3 when operating with Pascal

Available now at your local computer store

$295.00

Call Computer Stop for Store nearest you
Shipping, Insurance, Handling, extra

Dealer inquiries invited.

Contact:

COMPUTER STOP CORP.

2545 West 237th St.

Suite L

Torrance, CA 90505

539-7671

The Computer Stop

16919 Hawthorne Blvd.
Lawndale, CA 90260 -

( 213 ) 371-4010

Calif. Residents add 6% Sales Tax
•Apple is a Registered TM of Apple Computers, Inc.

MON. - SAT.

10-6

u* Reader Service index — page 24 1

Microcomputing, October 1980 39

Address List Program

Machine-language program for 6800 users who want to keep up to date on who’s who.

*J 00RD

FUNCTION <N,B,Z,L,

F,E,A,S,D) ? N

DAWSON; HAROLD *

453 287 5496

310427

4730 FULTON RD.

JACKSON; MI

76321

JACKSON; JOHN

301 251 6436

290403

243 AMOS ST.

newburg; mo

33557

VARREL; PHVLLIS

474 976 3287

340323

455 53RD ST.

SflN FRANCISCO; Cfl 34567

Example 2. Normal operation. Entry at $00 AD. Name sort.

NAME <20 CHRRRCTERS )
JACKSON; JOHN,

TELEPHONE <11 DIGIT MAX)

3012516486

BIRTH DRTE < WMMDD)

290403

STREET <21 CHRRRCTERS >

243 RMOS ST.,

CITV;STRTE <17 CHARACTERS)
NEUBURG; MO,

ZIP CODE <5 DIGITS)

33557

NflME <20 CHRRRCTERS)
DAWSON; HflROLD *,
TELEPHONE <11 DIGIT MfiX)
4532875496
BIRTH DATE (WMMDD)

318427

STREET <21 CHRRRCTERS)
4730 FULTON RD. ,

C I TV ; STATE <17 CHARACTERS)
JACKSON# MI,

ZIP CODE <5 DIGITS)

76321

NAME <20 CHARACTERS)

VARREL ; PHVLLIS,

TELEPHONE <11 DIGIT MfiX)

4749763287

BIRTH DRTE < WMMDD)

340823

STREET <21 CHARACTERS)

455 53RD ST. ,

Cl TVJ STATE <17 CHRRRCTERS)
SAN FRANCISCOJ Cfl
ZIP CODE <5 DIGITS)

34567

NflME <20 CHRRRCTERS)

i

Example 1. Initial use. Entry at $0100.
Shows initial entries and stops with an
exclamation point (!).

N — Sort by name
Z — Sort by zip code
F— List “flagged" entries
A — Add an entry

D- Delete an entry by sub-command as under S
B — Sort by birth year
L- List as currently sorted
E — Exit to Monitor (or File Manager)

S — Select an entry by sub-command:

# — name (#name#)

B — birth month (B04B)

Z-zip code (Z20783Z)

Table 1.

C.H. Looney

3406 Notre Dame Street

Hyattsville, MD 20783

T his machine-language program is for in-
serting, retrieving, sorting and deleting
name, address and birth date information.

The program takes about 1200 bytes of
storage. At least 80 entries can be stored in
an 8K machine.

Sorting is done by the primitive “bubble”
method. It takes about one second to sort
25 entries and about four seconds to sort 50
entries. Sorting can be done by name, birth
year or zip code.

Entries can be selected for printing or
viewing on a CRT terminal by name, birth
month, zip code or “flag.” The “flagged” en-
tries are marked by an asterisk after the
name. Entries can be deleted after selection
by name, birth month or zip code.

Function selection is by single letter in-
put, except for those operations involving
selection of a sort field (name, birth month
or zip code). The sort field can be as short or
as long as desired.

The functions are listed in Table 1.

The program (Listing 1) is particularly
valuable to 6800 users without disk capabil-
ity.

The first section of the program, from

00A3 to 00FF, is an executive to accept
commands and branch to the proper areas
of the program to accomplish the desired
results. Start the program at $0100 the first
time it is used to set up memory space and
get first entries. Succeeding uses should
enter at $00AD (EXEC) to add entries, sort,
print, delete entries and so on.

The listing was prepared with a disas-
sembler based on one described by Bob
Lentz in the May 1979 Byte. His disassem-
bler shows jump and branch destinations
by address; I have included the capability of
adding more conventional name destina-
tions and labels along with comments. You
may find the address destinations more
helpful in understanding the operation of
the program.

My interest in a name/address data-base
program was whetted by an article in the
October 1978 Kilobaud by Wantz and Bate-
man (“A Useful Address List Program,” p.
102). They wrote their program in BASIC,
however, and thus took a large amount of
memory, leaving only room for about 15 en-
tries in my 8K memory. This program pro-
vides space for more than 80 entries in that
8K of memory and sorts the entries in an ac-
ceptable time. Ambitious enthusiasts may
wish to put in a more advanced sorting pro-
gram, for both exercise and improvement.

The initialization section is the second

40 Microcomputing, October 1980

FUNCTION <N,B,Z,L,F,E,R,S,D> ? Z

JACKSON; JOHN
243 RMOS ST.

VRRREL; PHVLLIS
455 53RD ST.

druison; hrrold *

4730 FULTON RD.

301 251 6486 290403

NEWBURG; MO 33557

474 976 3287 340823

SRN FRRNCISCO; CR 34567

453 287 5496 310427

JRCKSON; MI 76321

Example 3. Birth year sort.

FUNCTION <N,B,Z,L,F,E,fl,S,D> ? B

JRCKSON; JOHN 301 251 6486

243 RMOS ST. NEWBURG; MO

290403

33557

DRUISON; HRROLD *. 453 287 5496

4730 FULTON RD. JRCKSON; MI

318427

76321

VRRREL; PHVLLIS 474 976 3287 348823

455 53RD ST. SRN FRRNCISCO; CR 34567

Example 4. Zip code sort.

FUNCTION <N,B,Z,L,F,E,fl,S,D> ? F

DAWSON; HRROLD * 453 237 5496

4730 FULTON RD. JRCKSON; MI

310427

76321

Example 5. Flag sort.

FUNCTION <N,B,Z,L,F,E,fl,S,D) ? S #Vfl R#

VRRREL; PHVLLIS 474 976 3287 340823

455 53RD ST. SRN FRANCISCO; CR 34567

Example 6. Selection of name by first three letters.

FUNCTION <N,B,Z,L,F,E,R,S,D> ? S B04B

JRCKSON; JOHN
243 RMOS ST.

301 251 6486 290403

NEWBURG; MO 33557

DRUISON; HAROLD *
4730 FULTON RD.

453 287 5496 310427

JRCKSON; MI 76321

Example 7. Selection by birth month (April— 04)

FUNCTION <N,B,Z,L,F,E,A,S,D> ? D Z76321Z
DELETE THIS ENTRV <V/N>?

DRUISON; HRROLD *
4730 FULTON RD.

453 237 5496 310427

JRCKSON; MI

76321

FUNCTION <N,B,Z,L,F,E,fl,S,D:> ? N

JRCKSON; JOHN
243 RMOS ST.

301 251 6486 290403

NEWBURG; MO

33557

VRRREL; PHVLLIS
455 53RD ST.

474 976 3287 340823

SRN FRRNCISCO; CR 34567

FUNCTION <N,B,Z,L,F,E, A,S,D!> ? E
CFM,-'3 UER 2.7

part of the program. It sets up the area for
storage of data from $0500 to $1310, allow-
ing for 45 entries. Additional space can be
allocated at $50 (80 decimal) spaces per en-
try.

The third section, the interrupt routine
starting at $016A, permits stopping the
printer on control-S and restarting on con-
trol-Q. This is particularly useful on a CRT
screen; information can be jotted down as
the entire data base is scanned. The inter-
rupt routine also permits returning to the
executive by typing in control-C either dur-
ing printing or during a pause.

The listing section, $019F through
$01 DD, sets up field lengths and branches
to the interrupt routine to print the entries.
LIST is a subroutine called by the executive
and other program sections to print entries
one at a time. SWTBUG routines are used
throughout this program for input (INCH-
E1AC), output (OUTCH-E1D1), printing a
space (OUTS-EOCC) and printing a string
ending with $04 (PDATA1-E07E).

The sorting routines starting at $01 DE
are based on ideas in “6800" Software
Gourmet Guide & Cook Book by Scelbi
Computer Consulting, Inc. This book is
ideal for the beginning 6800 user and is also
useful for the expert to use as a handbook
and reference. The sorting routines use the
primitive bubble sort, but with the relatively
small number of entries, sorting times are
not long. The first part of this section simply

Example 8. Deletion by zip code, name sort, return to Manager.

Listing 1.

***** EXECutive routine — Jumps or branches to routines on

bas i s

of i nput. c

ommands

00R3

81

44

CONTEX

CMP

R #44

# D

is it. a D?

00R5

26

06

BNE

00RD

EXEC:

if not-.* do to EXEC

00R7

7E

03B1

JMP

03B1

DELETE

else, do DELETE

00RR

7E

1780

JCFM

JMP

1730

CFMx3

do to File Manader

00RD

BD

0300

EXEC

JSR

0300

PC.RLF

print CR & LF

0080

CE

04BD

LDX

#04BD

#' FUNCTION. . . load menu index

08B3

BD

E87E

JSR

E07E

PDRTR1

and print menu

00B6

BD

El AC

JSR

E1RC

INCH

det a character

00B9

81

4E

CMP

R #4E

# N

is it. an N?

00BB

27

IF

BEQ

00DC:

JSORTN

if so, do sort by name

08BD

81

42

CMP

R #42

# B

is it. a B?

00BF

27

20

BEQ

00E1

JSORTB

if so, do sort by birth year

00C1

81

5R

CMP

R #5R

#'Z

is it. a Z?

00C3

27

21

BEQ

08E6

JSORTZ

if so, do sort by zip codes

00C5

81

4C

CMP

R #4C

#'L

is it an L?

00C7

27

20

BEQ

00E9

JLIST

if so, list entries

00C9

81

46

CMP

fl #46

#-F

is it- an F?

00CB

27

2B

BEQ

00F8

JFLRG

if so, list fl added entries

00CD

31

45

CMP

R #45

#E

is it an E?

00CF

27

D9

BEQ

00RR

JCFM

if so, do to Manader

00D1

81

41

CMP

R #41

#• A

is it an fl?

00D3

27

36

BEQ

010B

RESTRT

if so, do add an entr y

00D5

31

53

CMP

R #53

#S

is it. an S?

00D7

26

CR

BNE

00R3

CONTEX

if not, do to EXEC

00D9

7E

033C

JMP

038C

SELECT

else, select an entry

00DC

BD

01DE

JSORTN

JSR

01 DE

SORTN

do sort, by names

00DF

28

08

BRR

00E9

JLIST

and 1 i st entr i es

00E1

ED

020C

JSORTB

JSR

020C

SORTB

do sort by birth year-

00E4

20

03

BRR

00E9

JLIST

arid 1 i st entr i es

00E6

BD

01F5

JSORTZ

JSR

81F5

SORTZ

do sort by zip codes

00F9

BD

0300

JLIST

JSR

0308

PCRLF

print CR & LF

00EC

CE

0500

LDX

#0500

#DATfi

load data index

80EF

BD

019F

JSR

819F

LIST

and list the entries

00F2

6D

01

TST

X 01

throudh 1 i st. i nd?

00F4

26

F9

BNE

00EF

JLIST+6

i f not , cont i nue

00F6

28

B5

JEXEC

BRR

00RD

EXEC

else, do to EXEC

00F8

BD

0300

JFLRG

JSR

8300

PCRLF

print CR & LF

00FB

BD

0276

JSR

0276

FLAG

and list- fl added entries

00FE

28

F6

BRR

00F6

JEXEC

do to EXEC

***** START

routine

— clears de

sired memory area and

adds entr

ies to data

base

0100

CE

8500

START

LDX

#0500

#DATR

load data index

0103

6F

00

CLR

X 00

and clear memory location

0105

03

I NX

do to next location

0106

8C

1311

CF'X

#1311

#DATEND+ 1

end of data memory?

Microcomputing, October 1980 41

0109

26

F8

BNE

0103

STftRT+3

if not , do it adain

010B

CE

0500

RESTRT

LDX

#0500

#DftTfl

load data index

010E

BD

02E9

JSR

02E9

FNDEND

move to end of entries

0111

BD

0300

JSR

0300

PCRLF

print C\ \ LF

0114

36

0D

LDft

ft #0D

# ' CR

load a CR

0116

ft7

00

STft

ft X 00

and store it

0118

03

I NX

do to next location

0119

C6

14

LDft

B #14

name field 1 end t h

01 IB

3D

16

BSR

0133

PROMPT

do det a name

01 ID

C6

0ft

LDft

B #8ft

telephone number field lendth

01 IF

3D

12

BSR

0133

PROMPT

do det the number

0121

C6

06

LDft

B #06

birthdate field lendth

0123

8D

0E

BSR

0133

PROMPT

do det the date

0125

C6

15

LDft

B #15

street field lendth

0127

8D

0ft

BSR

0133

PROMPT

do det. the address

0129

C6

11

LDft

B #11

city/state field lendth

012B

8D

06

BSR

0133

PROMPT

do det- the city-state

01 2D

C6

05

LDft

B #05

zip code field lendth

01 2F

3D

02

BSR

0133

PROMPT

do det the zip

0131

20

D8

BRfi

01 0B

RESTRT

do back for another one

0133

DF

38

PROMPT

STX

D 38

SftUEXl

save the index

0135

Cl

14

CMP

B #14

is it the name field"?

0137

26

03

BNE

013C

if not> check next

0139

CE

0417

LDX

#0417

# ' NfiME . . .

else load name index

01 3C

Cl

0ft

CMP

B #0ft

is it the telephone field?

013E

26

03

BNE

0143

if not/ check next

0140

CE

0431

LDX

#0431

#'TEI

else load telephone index

0143

Cl

06

CMP

B #06

is it the birthdate field?

0145

26

03

BNE

014ft

if not .. check next

0147

CE

044 F

LDX

#044F

# 'BIRTH. .

.else load birthdate index

014ft

Cl

15

CMP

B #15

is it the street field?

014C

26

03

BNE

0151

if not... check next

014E

CE

0468

LDX

#0468

# STREET.

. . else 1 oad street i ndex

0151

Cl

11

CMP

B #11

is it the cityxstate field?

0153

26

03

BNE

0153

if not , check next

0155

CE

0484

LDX

#0434

#"CITV ..

. else load city/state index

0158

Cl

05

CMP

B #05

is it the zip code field?

015ft

26

03

BNE

015F

if no to do print

015C

CE

04ft4

LDX

#04ft4

#'ZIP...

else load zip index

015F

BD

E07E

JSR

E07E

PDftTftl

print messade

0162

DE

38

LDX

D 38

SftUEXl

reload index

0164

BD

0300

JSR

0300

PCRLF

print- CR & LF

0167

7E

029B

JMP

029B

INPUT

now do det the keyboard input.

***** Interrupt, routine -

permits

stopp i nd

and restart ind the

pr i nt rout i ne or

return ind to EXEC

016ft

B6

8004

INTRUP

LDft

ft 8004

look at key board address

01 6D

47

ftSR

ft

any act- i on?

016E

24

IF

BCC

018F

CONTP

if not, continue print ind

0170

B6

8005

LDft

ft 8005

else load keyboard entry

0173

81

03

CMP

ft #03

#'TC

is it a Control -C?

0175

26

03

BNE

017ft

if not-., check for another

0177

7E

00ftD

JEXEC1

JMP

00RD

EXEC

else return to EXEC

017ft

31

13

CMP

ft #13

#"TS

is it a Control -S?

01 7C

26

11

BNE

018F

CONTP

if not., continue print ind

017E

B6

3004

LOOP

LDft

ft 8004

look at keyboard address

0181

47

RSR

ft

any action?

0182

24

FR

BCC

01 7E

LOOP

if not., continue loop ind

0184

B6

3005

LDft

ft 3005

else load keyboard entry

0187

31

03

CMP

ft #03

# X TC

is it. a Control— C?

0139

27

EC

BEQ

0177

JEXEC

if soj return to EXEC

013B

81

11

CMP

ft #11

#'TQ

is it. a Control -Q?

01 3D

26

EF

BNE

01 7E

LOOP

if not , continue loop ind

013F

ft6

00

COHTP

LDft

ft X 00

det character from memory

0191

81

00

CMP

ft #00

is it 00?

0193

26

02

BNE

0197

OUTC

if not, do print it

0195

36

20

LDft

ft #20

# 'SP

else load a space

0197

BD

E1D1

OUTC

JSR

E1D1

OUTCH

arid print it

019ft

08

I NX

do to next memory location

019B

5fl

DEC

B

decrement the counter

019C

26

CC

BNE

016ft

INTRUP

if not throudh, det another

019E

39

RTS

else return

*****

LIST routine -

set •»

up field counters

and branches to

INTRUP to list name , birthdate, tel hone
number and address information

019F

C6

15 LIST

LDft B #15

CR + name field lendth

01R1

8D

C7

BSR 016R

INTRUP

do print, name

01R3

BD

E0CC

JSR E0CC

OUTS

print a space

01R6

C6

03

LDft B #03

tel. area code field lendth

01RS

3D

C0

BSR 016ft

INTRUP

do print area code

01Rft

BD

E0CC

JSR E0CC

OUTS

print a space

01RD

C6

03

LDft B #03

tel. exchande field lendth

01RF

3D

B9

BSR 016ft

INTRUP

do print, exchande

01B1

BD

E0CC

JSR E0CC:

OUTS

print a space

01B4

C6

04

LDft B #04

tel. number field lendth

01B6

3D

B2

BSR 016ft

INTRUP

do print number-

01B8

BD

E0CC

JSR E0C.C.

OUTS

print a space

01BB

BD

E0CC

JSR E0CC:

OUTS

print, another space

01BE

C6

06

LDft B #06

birthdate field lendth

01C0

8D

R8

BSR 016R

INTRUP

do print birthdate

01C2

BD

0300

JSR 0300

PCRLF

print CR & LF

01C5

C6

15

LDft B #15

street field lendth

01C7

3D

R1

BSR 016ft

INTRUP

do print street address

01C9

BD

E0CC

JSR E0C.C

OUTS

print a space

01CC

C6

11

LDft B #11

cityxstate field lendth

01CE

3D

9ft

BSR 016ft

INTRUP

do print cityxstate

01D0

BD

E0C.C:

JSR E0CC

OUTS

pr i nt a ;p ace

01D3

C6

05

LDft B #05

zip code field lendth

01D5

3D

93

BSR 016ft

INTRUP

do print- zip

01D7

BD

0300

JSR 0300

PCRLF

print CR & LF

01DR

BD

0300

JSR 0300

PCRLF

print C-R & LF

01DD

39

RTS

and return

sets up field lengths and starting locations
in order to ease the user’s problems in di-
recting sorting operations.

The flag routine ($0276 through $0299)
searches for the flag (an asterisk—*) and
uses LIST to print selected entries. The flag
need not be at any particular location as
long as it is in the name field. It could pre-
cede names for selection, be buried in the
name or follow the names to be selected.

The input routine starting at $029B is
used to format the input data, to recognize
when input is completed and to permit
back-space correction or entry canceling.
The exclamation point (!) is used to stop en-
try and return to the executive. It should be
used as the first character in an entry field;
otherwise, a partial entry will be made.

Telephone numbers, birth dates and zip
codes are expected to fill designated fields,
while names and addresses may be trun-
cated by using a comma as the final charac-
ter. The comma can also be used to blank a
field when the data is unknown by typing
the comma as the first character in that
field. If a field is overrun, the overflow char-
acters will fall into the next field; therefore,
you must be careful when filling entries.

Since a comma is used to truncate
names and addresses, a semicolon should
be used to separate city from state and last
name from initials. You can use a return
(CR) to terminate an entry and cause the
program to consider that entry complete
and prepare for the next entry.

The two routines next in line simply print
a CR and LF and advise you when the last
entry space has been filled.

The rest of the program is based on the
excellent ideas put forth by Peter Stark’s ar-
ticle on a BASIC editor (see “An Editor for
6800 BASIC Programs,” January 1979 Kilo-
baud Microcomputing, p. 22). In particular,
his search and replace routines have been
adapted to the needs of this data-base pro-
gram.

SELECT and DELETE are the two primary
routines. Each uses DELIM to set up a de-
limiter character and READST to set up a
string for matching to names, birth months
or zip codes in the stored data. The delim-
iter character must be a number sign (#) for
use in selecting names, B for choosing birth
months and Z for selecting zip codes.

SELECT will print out as many entries as
have matching characteristics with the
string. DELETE will ask you whether you
wish to delete an entry chosen to match the
string. If you do not accept the offered en-
try, DELETE will go back to get another until
all matching entries have been offered.

Listing 2 is a complete machine-code list-
ing of the program followed by a decoded
printout of the character strings used as
messages. Examples 1-8 show the use of
the data-base program. ■

42 Microcomputing, October 1980

***** SORT routines — name * birth year and zip code sort routines

01DE

CE

022R

SORTN

LDX

#0228

index for sort- field length

01E1

36

14

LDR

R #14

name sort field length

01E3

R7

00

STR

R X 00

01E5

86

01

LDR

R #01

name field start location

01E7

R7

09

STR

R X 09

01E9

86

51

LDR

R #51

next name field start-

01EB

R7

0B *

STR

R X 0B

01 ED

86

3C

LDR

R #3C

distance to next name field

01EF

R7

13

STR

R X 13

01F1

R7

42

STR

R X 42

01F3

20

2C-

BRR

0221

SORT

3o do the sort i na

01F5

CE

022R

SORTZ

LDX

#022R

index for sort field lenat-h

01FS

86

05

LDR

fl #05

zip code field len3th

01FR

R7

00

STR

R X 00

01FC

86

4B

LDR

fl #46

zip code field start location

01FE

R7

09

STR

R X 09

0200

86

9B

LDR

R #96

location of next zip

0202

R7

0B

STR

R X 0B

0204

36

4B

LDR

R #4B

distance to next zip

0206

R7

13

STR

R X 13

0208

R7

42

STR

fl X 42

020FI

20

15

BRR

0221

SORT

3o do the sort i na

020C

CE

022R

S0RTB

LDX

#0228

index for s art field length

020F

86

06

LDR

fl #06

birthdate field len3th

0211

R7

00

STR

fl X 00

0213

36

IF

LDR

R #1F

birthdate field start location

0215

R7

09

STR

R X 09

0217

86

6F

LDR

R #6F

location of next birthdate

0219

R7

0B

STR

fl X 0B

021B

86

4R

LDR

R #4R

di stance to next birthdate

021D

R7

13

STR

fl X 13

02 IF

R7

42

STR

fl X 42

0221

CE

0500

SORT

LDX

#0500

#DATA

1 oad data i ndex

0224

SC

12C0

NEREND

CPX

#12C0

#DRTEND-

$50 index of last possible entry

0227

27

06

BEQ

022F

SRTRET

return if at last entry

0229

C6

14

LDR

B #14

sort field len3th

022B

6D

51

TST

X 51

check to see if at data end

022D

26

01

BNE

0230

CKNEXT

if not* continue

022F

39

SRTRET

RTS

else return

0230

DF

38

CKNEXT

STX

D 33

SRUEX1

save i ndex

0232

R6

01

LDR

R X 01

load character

0234

R1

51

CMP

R X 51

compare with next field

0236

26

0C

BNE

0244

CKGTLT

if not same* see which laraer

0238

03

I NX

else move on

0239

5R

DEC

B

arid decrement counter

023R

26

F6

BNE

0232

CKNEXT +2

continue if not at field end

023C

C6

3C

LDR

B #3C

else 3o to next field

023E

03

I NX

by adoancina step

023F

5R

DEC

B

by step

0240

26

FC

BNE

023E

keep at it till at next field

0242

20

E0

BRR

0224

NEREND

arid sort- next pair of fields

0244

23

21

CKGTLT

BLS

0267

F INEND

if less 3o to field end

0246

C6

50

LDR

B #50

else bubble sort them

0248

DE

33

LDX

D 33

SAUEX1

by saoina the index

024R

R6

00

NOT VET

LDR

R X 00

arid interchanaina characters

024C

97

35

STR

R D 35

TEMP

between DRTR and TEMP locations

024E

R6

50

LDR

R X 50

unt i 1 they ' re all

0250

A7

00

STR

R X 00

i nterchanaed

0252

96

35

LDR

R D 35

TEMP

0254

R7

50

STR

R X 50

0256

03

I NX

0257

5fl

DEC

B

0258

26

F0

BNE

024R

NOTVET

keep at it till done

025R

C6

R0

LDR

B #R0

and then load the counter

025C

09

NMINUS

DEX

to backup two entries

025D

sn

DEC

B

now 3o back to last entry

025E

26

FC

BNE

025C

NMINUS

to see if it needs to move

0260

3C

0500

CPX

#0500

#DRTR

but don ' t 3o too f ar

0263

2D

BC

BL.T

0221

SORT

if so* 3o back and sort aaain

0265

20

BD

BRR

0224

NEREND

else continue from here

0267

03

F INEND

I NX

now ao to field end

0263

5fl

DEC

B

step by step

0269

26

FC

BNE

0267

F INEND

there yet?

0266

C6

3C

LDR

B #3C

ok.* now ao to next sort field

026D

03

I NX

step by step

026E

5fl

DEC

B

026F

26

FC

BNE

026D

once you're there

0271

20

B1

BRR

0224

NEREND

sort the next pair of fields

0273

7E

010B

JRES

JMP

010B

RESTRT

used as a Jump island

***** FLRG rout. in© -

to select and print, flawed entries

0276

CE

0500

FLRG

LDX

#0500

#DRTR

data start index

0279

06

15

LDR

B #15

CR + name field lenath

027B

R6

00

LDR

R X 00

3et a character from memory

027D

81

2fl

CMP

fl #28

#•*

is it the flaa <*>?

027F

27

0F

BEQ

0290

BACK

if so* 3o back uf

0281

08

I NX

if not* 3o to next, character

0282

5fi

DEC

B

decr ement- the counter

0283

26

F6

BNE

027B

if not. at. field end* do aaain

0285

C6

3B

LDR

B #3B

else 3o to next field

0287

08

I NX

step by step

0283

5R

DEC

B

at end yet?

0289

26

FC

BNE

0287

if not* do it aaain

028B

R6

00

LDR

R X 00

then 3et a character

028D

26

ER

BNE

0279

FLflG+3

if not 00* check this field

023F

39

RTS

else return

0290

09

BACK

DEX

back up to start of

0291

5C

INC

B

name field

0292

Cl

15

CMP

B #15

throuah yet.?

0294

26

FR

BNE

0290

BACK

if not* keep backina

0296

BD

01 9F

JSR

019F

LIST

else ao 1 i st entry

0299

20

DE

BRR

0279

FLflG+3

arid look for next flaa

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Reader Service index— page 241

Microcomputing, October 1980 43

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***** INPUT routine - accepts input data and puts in correct place

029B

BD

ElftC

INPUT

JSR

ElflC

INCH

det character- from keyboard

029E

31

21

CMP

R #21

#' !

is it an !?

02R0

26

03

BNE

02R5

if not., continue

02R2

7E

00RD

JMP

00RD

EXEC

else do to EXEC

02R5

SI

0F

CMP

R #0F

#'TQ

is it Contro 1 -0?

02R7

26

10

BNE

02B9

CONT

if not* continue

02R9

CE

0500

LDX

#0500

#DflTfl

else load DATA index

02RC

8D

36

BSR

02E9

FNDEND

find end of entries

02RE

C6

50

LDR

B #50

set counter for entry space

02B0

09

BfiCKUP

DEX

and backup to start

0261

5R

DEC

B

of current entry

02B2

26

FC

BNE

02B0

BACKUP

if not done , do adain

02B4

6F

00

CLR

X 00

clear first location

0266

7E

0111

JMP

0111

RESTRT+6

and start entry adain

0269

81

0D

CONT

CMP

fl #0D

#'CR

is it a CR?

02BB

27

66

BEG

0273

JRES

if so. do back to RESTRT

02BD

31

08

CMP

R #08

#"BS

is it a BS?

02BF

26

0E

BNE

02CF

CONTI

i f riot , cont i nue

02C1

09

DEX

else backup one

02C2

SC

INC

B

space., and

02C3

36

PSH

R

save ACC fl

02C4

R6

00

LDR

fl X 00

det. a character

02C6

31

0D

CMP

R #0D

#'CR

is it a CR?

02C8

32

PUL

fl

restore RCC R

02C9

26

D0

BNE

029B

INPUT

if not CR.. det keyboard entry

02CB

08

I NX

else do forward

02CC

5fl

DEC

B

a space

02CD

20

CC

BRR

029B

INPUT

arid det the entry

02CF

81

2C

CONTI

CMP

fl #2C

#'*

is it a *?

02D1

26

0R

BNE

02DD

C0NT2

if not., continue

02D3

86

00

HRUECM

LDR

fl #00

else load 00

02D5

R7

00

STR

fl X 00

and store to fill

02D7

08

I NX

until field is full

02D3

5R

DEC

B

full field?

02D9

26

F8

BNE

02D3

HRUECM

if not* repeat

02DB

20

06

BRR

02E3

RETURN

else start back for another one

02DD

R7

00

C0NT2

STR

R X 00

store the character

02DF

08

I NX

arid bump the index counter-

02E0

5fl

DEC

B

decrement counter; field full?

02E1

26

04

BNE

02E7

C0NT3

if not* do C0NT3

02E3

BD

E0CC

RETURN

JSR

E0CC

OUTS

else print a space

02E6

39

RTS

arid return

02E7

20

B2

C0NT3

BRR

029B

INPUT

do for more input

02E9

6D

01

FNDEND

TST

X 01

look at next, character

02E6

27

0R

BEG

02F7

ENDRET

if 00.. return

02ED

C6

50

LDR

B #50

else load counter

02EF

03

BOUNCE

I NX

and move ahead

02F0

5R

DEC

B

step by step

02F1

26

FC

BNE

02EF

RDUNCE

if not throudh* keep adoancind

02F3

8D

05

BSR

02FR

CKSPRC

do check if at end

02F5

20

F2

BRR

02E9

FNDEND

arid see if at next empty spot

02F7

01

ENDRET

NOP

02FS

01

NOP

02F9

39

RTS

do back where you came from

02FR

SC

1310

CKSPRC

CPX

#1310

#DflTEND

end of space <45 entries)

02FD

27

0C

BEG

030B

MEMFUL

if at end* tell user

02FF

39

RTS

else return

***** CR LF routine -

prints a CR

& LF

0300

DF

38

PCRLF

STX

D 38

SAUEX1

store the index

0302

CE

0400

LDX

#0400

#'CR LF. . .

.load messade index

0305

BD

E07E

JSR

E07E

PDRTfll

print the CR & LF

0308

DE

38

LDX

D 38

SflUEXl

restore index

030R

39

RTS

and return

***** MEMor-y

FUL1 Routine

- prints MEMORY FULL when allocated

memory space is

f i 1 led

0306

CE

0406

MEMFUL

LDX

#0406

# 'MEM. . .

load messade index

030E

BD

E07E

JSR

E07E

PDRTfll

print the messade

0311

7E

1730

JMP

1780

CFM/3

and return to Manader

***** READ STrind routine

- accepts keyboard input, of string to be

found

in DATA

0314

BD

ElflC

RERDST

JSR

ElflC

INCH

det keyboard i nput

0317

11

CBR

compare with RCC B

0318

27

09

BEG

0323

EXITRS

if eaual* return

031fi

81

0D

CMP

fl #0D

#'CR

is it a CR?

03 1C

27

05

BEG

0323

EXITRS

if so* return

031E

R7

00

STR

fl X 00

else store the character

0320

03

I NX

bump the index and

0321

20

FI

BRR

0314

REflDST

do back for another input

0323

39

EXITRS

RTS

return

DIGITAL MARKETING

2670 Cherry Lone
Ulolnut Creek, CO 94596
(415) 938-2880 ✓ ei

INVENTORY 1 & 2, MAILROOM, P/M PLANNER,
HOUSEKEEPER I & II. & TOOL-1 are trademarks
of the Software Works, Inc. TEXTWRITER III IS A
TRADEMARK OF ORGANIC SOFWARE

***** FIND STrind routine

- searches for STRING; if found returns

with

RCC B = 1

0324

96

40

FINDST

LDR

fl D 40

STRING- 1

det- the delimiter

0326

81

23

CMP

fl #23

#'#

is it a #?

0323

27

16

BEG

0340

NFIND

if so* do lookind for- a name

032R

81

5ft

CMP

R #5fl

#'Z

is it a Z?

032C

27

0C

BEG

033R

ZFIND-2

if so* do lookind for a zip

032E

81

42

CMP

R #42

#'B

is it. a B?

0330

26

67

BNE

0399

JEXEC2

if not* do to EXEC

***** select

routine

— prints entries based

on user selection

of

name*

zip code or

birthdate

038C

8D

EC

SELECT

BSR

037R

DELIM

det. delimiter and STRING

033E

CE

0500

LDX

#0500

#DRTR

load DATA index

0391

BD

0300

JSR

0300

PCRLF

print CR & LF

44 Microcomputing, October 1980

THE

HiD'STLHNTiC
— COMPUTER —
SHOW

WASHINGTON, D.C.

D C. ARMORY/STARPLEX
THURSDAY-SUNDAY
SEPTEMBER 18-21
11 A M TO 9 P.M. THURS.-SAT.
11 A M. TO 5 P.M. SUN.

THE

NHTiONHL

CONFUTES

SHOWS

HAVE WE
COT A PROGRAM
FOR YOU!

Please send me:

The new computers are showing off.

Over $50 million worth of equipment in over 100,000
square feet of space, including the latest software and hard-
ware for business, government, home and personal use. Every-
thing the NCC show has and more will be on display, and you can
buy it all right on the spot.

Computers costing $150 to $250,000, mini and micro com-
puters, data- and word-processing equipment, telecommunica-
tions, office machines, peripheral equipment and services from
leading names in the industry like IBM, Xerox, Radio Shack
and Apple will all be there.

There’ll be conferences on business uses of small to
medium sized computers, and howto make purchasing
evaluations.

There’ll be robots, computerized video games,
computer art and computer music.

Everyone from kids to people who earn their liv-
ing with computers will have a great time at the larg-
est computer show ever organized in each region.
Admission for adults is $5. The public is
invited, and no pre-registration is necessary.
Don’t miss the computer show that
mixes business with pleasure. Show
up for the show.

THE

LOMrlilLn

SHOH

CHICAGO

McCORMICK PLACE
THURSDAY-SUNDAY
OCTOBER 16-19
11 A.M. TO 9 PM. THURS.-SAT.
11 A.M. TO 5 P.M. SUN.

Produced by National Computer Shows,
824 Boylston Street, Chestnut Hill, MA 02167.
Telephone (617) 739-2000.

NORTHERS!
COHFUTER
SHOH

BOSTON

HYNES AUDITORIUM
PRUDENTIAL CENTER
THURSDAY-SUNDAY
NOVEMBER 20-23

11 A.M. TO 9 P.M. THURS.-SAT.
11 A.M. TO 5 P.M. SUN.

□ adult tickets at $5 each. I have enclosed the proper amount of $

□ Information on the show's conference program.

□ Hotel registration information □ Exhibitor rental information

Please print: Name „

Address

City State Zip

Reader Service index— page 241

Microcomputing, October 1980 45

MORE FOR YOUR 3
RADIO SHACK TRS-80
MODEL I !

★ MORE SPEED

10-20 times faster than Level II BASIC.

★ MORE ROOM

Compiled code plus VIRTUAL
MEMORY makes your RAM act larger.

0394

8D

3E

FLOOP

BSR

0324

FINDST

do find the STRING

0396

5D

TST

B

find one?

0397

26

03

BNE

039C

LQOKCR

if so, do back to CR

0399

7E

00RD

JEXEC2

JMP

00RD

EXEC

else do EXEC

039C

09

LQOKCR

DEX

start backind up

039D

06

00

LDR

R X 00

det a character

039F

SI

0D

CMP

R #0D

# •' CR

is it a CR?

03fll

26

F9

BNE

039C

LQOKCR

if not, keep backind

03R3

BD

01 9F

JSR

019F

LIST

else print entry

03R6

6D

01

TST

X 01

is it the last one?

03R8

27

EF

BEQ

0399

JEXEC2

if so, do EXEC

03RR

8C

1310

CPX

#1310

#DRTEND

at end of memory?

03RD

26

E5

BNE

0394

FLOOP

if not, look for another

03RF

20

E8

BRR

0399

JEXEC2

else do EXEC

★ MORE INSTRUCTIONS

Add YOUR commands to its large in-
struction set!

Far more complete than most Forths:
single & double precision, arrays,
string-handling, more.

★ MORE EASE

Excellent full-screen Editor, structured
& modular programming
Optimized for your TRS-80 with
keyboard repeats, upper/lower case
display driver, single- & double-width
graphics, etc.

★ MORE POWER

Forth operating system
Interpreter AND compiler
Internal 8080 Assembler
(Z80 Assembler also available)

VIRTUAL I/O for video and printer,
disk and tape

(10-Megabyte hard disk available)

nt FORTH

THE PROFESSIONAL FORTH
FOR TRS-80

Prices!

MMSFORTH Disk System VI. 9 (requires 1

disk drive & 16K RAM) just $79.95*

MMSFORTH Cassette System VI. 8 (requires
Level II BASIC & 16K RAM) $59.95*

AND MMS GIVES IT
PROFESSIONAL SUPPORT

Source code provided
MMSFORTH Newsletter
Programming staff available
Many demo programs aboard
MMSFORTH User Groups

FLOATING POINT MATH (L.2 BASIC ROM
routines plus Complex numbers,
Rectangular-Polar coordinate conversions,
Degrees mode, more), plus a full Z80
ASSEMBLER; all on one diskette . . . $29.95*

THE DATAHANDLER, a very sophisticated
database management system operable by
non-programmers (requires 1 drive and 32K
RAM); with manuals $59.95*

Other packages under development

FORTH BOOKS AVAILABLE

MICROFORTH PRIMER — comes with

MMSFORTH; separately $15.00*

USING FORTH — more detailed and advanc-
ed than above $25.00*

URTH TUTORIAL MANUAL — very readable

intro, to U/Rochester Forth $19.95*

CALTECH FORTH MANUAL — good on
Forth internal structure, etc $6.95*

* — Software prices are for single-system
user license and include manuals. Add $2.00
S/H plus $1.00 per additional book; Mass,
orders add 5% tax. Foreign orders add 15%.
UPS COD, VISA & M/C accepted; no unpaid
purchase orders, please.

Send SASE for free MMSFORTH information.

Good dealers sought.

MMSFORTH is available from your
computer dealer or

MILLER MICROCOMPUTER
SERVICES (K10) 255

61 Lake Shore Road, Natick, MA 01760
(617) 653-6136

***** DELETE routine - deletes one entry based upon user's choice
of name , zip or birt-hdate; dels user
confirmation before deleting entry

0381

BD

037R

DELETE

JSR

037R

DELIM

det delimiter and STRING

03B4

CE

0500

LDX

#0500

#DRTR

load DRTR index

03B7

BD

0324

RPTDEL

JSR

0324

FINDST

find the STRING

03BR

5D

TST

B

find one?

03BB

26

02

BNE

03BF

LOOKC

if so, back up to a CR

03 BO

20

DR

BRR

0399

JEXEC2

if not , do EXEC

03BF

09

LOOKC

DEX

start, backind up

03C0

R6

00

LDR

R X 00

det a character

03C2

81

0D

CMP

fi #0D

#'CR

is it a CR?

03C4

26

F9

BNE

03BF

LOOKC

if not, keep backind

03C6

BC>

0300

JSR

0300

PCRLF

print CR & LF

03C9

CE

04 DD

LDX

#04DD

# DEI

load messade- index

03CC:

BD

E07E

JSR

E07E

PDRTR1

and print messade

03CF

DE

38

LDX

D 38

SRUEX1

save the i ndex

03D1

BD

019F

JSR

019F

LIST

print the entry

03D4

BD

E1RC

JSR

E1RC

INCH

det a character from keyboard

03D7

SI

59

CMP

R #59

#'V

is it a V?

03D9

27

0B

BEQ

03E6

DELET1

if so, do delete the entry

03DB

6D

01

TST

X 01

last entry?

03DD

27

BR

BEQ

0399

JEXEC2

if so, do EXEC

03DF

SC

1310

CPX

#1310

#DRTEND

end of memory?

03E2

26

D3

BNE

03B7

RPTDEL

if not, check another entry

03E4

20

B3

BRR

0399

JEXEC2

else do EXEC

03E6

09

DELET1

DEX

start, backind up

03E7

R6

00

LDR

R X 00

load a character

03E9

81

0D

CMP

R #0D

# 'CR

is it a CR?

03EB

26

F9

BNE

03E6

DELET1

if not, keep backind

03ED

86

5B

LDR

R #5B

#'C

load a C

03EF

R7

01

STR

R X 01

and store as 1st entry char.

03F1

BD

01DE

JSR

0 1 DE

SORTN

do SORTN to put this entry last

03F4

C6

50

LDR

B #50

load counter with entry size

03F6

08

CLERR

I NX

bump the index

03F7

6F

00

CLR

X 00

clear a character

03F9

5R

DEC

B

decrement the counter; at end?

03FR

26

FR

BNE

03F6

CLERR

if not, do adain

03FC

20

9B

BRR

0399

JEXEC2

when done, do EXEC

6332

C6

20

LDR

B #20

load the counter to det to

0334

08

BFIND

I NX

birthdate location arid move it

0335

5R

DEC

B

there - throudh?

0336

26

FC

BNE

0334

BFIND

if not, keep movind

0338

20

06

BRR

0340

NFIND

else do lookind

033R

C6

4fl

LDR

B #4R

load the counter to det. to

033C

08

ZFIND

I NX

zip code location and move it

033D

5R

DEC

B

there - throudh?

033E

26

FC

BNE

033C

ZFIND

if not, keep movind

0340

08

NFIND

I NX

now move one more space

0341

R6

00

LDR

R X 00

load a character

0343

91

41

CMP

fl D 41

STRING

match 1st STRING character?

0345

26

25

BNE

036C

NOTF

if not, do housekeep and return

0347

DF

3R

FOUND 1

STX

D 3R

SRUEX

else save index here

0349

DF

3C

STX

D 3C

TEMPSO

and here

034B

CE

0041

LDX

#0041

#STR I NG

then load STRING index

034E

DF

3E

STX

D 3E

TEMPST

and store it. here

0350

DE

3C

FLOOP 1

LDX

D 3C

TEMPSO

now load "data" index

0352

R6

00

LDR

R X 00

and put the 1st char, in fiCC R

0354

0S

I NX

bump the index

0355

DF

3C

STX

D 3C

TEMPSO

and store new index

0357

DE

3E

LDX

D 3E

TEMPST

load STRING index

0359

E6

00

LDR

B X 00

and put. its 1st char, in fiCC B

035B

08

I NX

bump its index

035C

DF

3E

STX

D 3E

TEMPST

and store i t

035E

11

CBR

do characters match?

035F

26

09

BNE

036R

NGTF-2

if not., do housekeep and return

0361

9C

36

CPX

R D 36

SPOIN

else see if at. end of STRING

0363

26

EB

BNE

0350

FLOOP 1

if not compare next characters

0365

DE

3R

LDX

D 3R

SRUEX

else load oridinal index

0367

C6

01

LDR

B #01

set RCC B to 1 and

0369

39

RTS

return

***** HOT Found routine -

resets

index and

sets RCC B to 0

if STRING not found

036R

DE

3fl

LDX

D 3R

SRUEX

load index

036C

08

NOTF

I NX

and start lookind for a CR

036D

R6

00

LDR

R X 00

det a character

036F

81

0D

CMP

R #0D

# ■' CR

is it a CR?

0371

26

F9

BNE

036C

NOTF

if not, look adain

0373

6D

01

TST

X 01

is next character- a 00?

0375

26

RD

BNE

0324

FINDST

if not, look for STRING adain

8377

06

00

LDR

B #00

else set. RCC B to 00

0379

39

RTS

arid return

***** DELIMiter routine - dets and stores the delimiter character

used to select, name.* zip, or birt-hdate
information

46 Microcomputing, October 1980

037R CE 0040 DELIM
037D BD E0C-C
0380 BO E1RC

0383 16

0384 R7 00

0386 08

0387 80 8B
0389 DF 36
038B 39

LDX #0040
JSR E0CC
JSR E1RC

STR R X 00
I NX

BSR 0314
STX 0 36
RTS

#STRING-1 set- index for delimiter
OUTS print a space

INCH 3et the delimiter

put it in RCC B
and in indexed location
bump the index and
RERDST ao Set STRING

SPG IN store index for end of STR I Hu

and return

Listing 2.

00R0

02

21

00

31

44

26

06

7E

03

B1

7E

17

30

BD

03

00

00B0

CE

04

BD

BD

E0

7E

BD

El

RC-

81

4E

27

IF

81

42

27

00C0

20

81

5R

27

21

31

4C

27

20

31

46

27

2B

81

45

27

0000

D9

31

41

27

36

81

53

26

CR

7E

03

8C

B0

01

DE

28

00E0

08

BD

02

0C

20

03

BD

01

F5

BD

03

00

CE

05

00

BD

00F0

01

9F

60

01

26

F9

20

B5

BD

03

00

BD

02

76

20

F6

0100

CE

05

00

6F

00

08

8C

13

11

26

F8

CE

05

00

BD

02

0110

E9

BD

03

00

86

00

R7

00

03

C6

14

SD

16

C6

0R

80

0120

12

C6

06

3D

0E

C6

1 5

3D

0R

C6

11

SD

06

C6

05

30

0130

02

20

08

DF

38

Cl

14

26

03

CE

04

17

Cl

0R

26

03

0140

CE

04

31

Cl

06

26

03

CE

04

4F

Cl

15

26

03

CE

04

0150

68

Cl

11

26

03

CE

04

84

Cl

05

26

03

CE

04

R4

BD

0160

E0

7E

DE

38

BD

03

00

7E

02

9B

B6

30

04

47

24

IF

0170

B6

80

05

81

©3

26

03

7E

00

RD

31

13

26

11

B6

80

0180

04

47

24

FR

B6

80

05

3 1

03

27

EC

31

11

26

EF

R6

0190

00

81

00

26

02

36

20

BD

El

01

08

5R

26

CC

39

C6

01R0

15

SD

C7

BD

E0

CC

C6

03

3D

C0

BD

E0

CC

C6

03

3D

01B0

B9

BD

E0

CC

C6

04

3D

B2

BD

E0

C-C

BD

E0

CC

C6

86

01C0

80

R3

BD

03

00

C6

1 5

SD

R1

BD

E0

CC

C6

11

80

9R

01D0

BD

EG

CC

C6

05

8D

93

BD

03

00

BD

03

00

39

CE

02

01E0

2fl

36

14

R7

00

86

01

R7

09

36

51

R7

0B

86

3C

R7

01F0

13

R7

42

20

2C

CE

02

2R

86

05

R7

00

86

4B

R7

09

0200

86

9B

R7

0B

86

4B

R7

13

R7

42

20

15

CE

02

2R

36

0210

06

R7

00

86

IF

R7

09

S6

6F

R7

0B

86

4R

R7

13

R7

0220

42

CE

05

00

SC

12

C0

27

06

C6

14

6D

51

26

01

39

0230

DF

38

R6

01

R1

51

26

0C

08

5R

26

F6

C6

3C

08

5R

0240

26

FC

20

E0

23

21

C6

50

DE

38

R6

00

97

35

R6

50

0250

R7

00

96

35

R7

50

08

5R

26

F0

C6

R0

09

5R

26

FC

0260

8C

05

00

2D

BC.

20

BD

08

5R

26

FC

C6

3C

08

5R

26

0270

FC

20

B1

7E

01

0B

CE

05

00

C6

15

R6

00

31

2R

27

0230

0F

08

5R

26

F6

C6

3B

08

5R

26

FC

R6

00

26

Eh

39

0290

09

5C

Cl

15

26

FR

BD

01

9F

20

DE

BD

El

RC

31

21

02R0

26

03

7E

00

RD

81

0F

26

10

CE

05

00

80

3B

C6

50

02B0

09

5R

26

FC

6F

00

7E

01

11

81

00

27

B6

81

08

26

02C0

0E

09

5C

36

R6

00

81

00

32

26

00

08

5R

20

CC

31

0200

2C

26

0R

36

00

R7

00

03

5R

26

F8

20

06

R7

00

08

02E0

5R

26

04

BD

E0

CC

39

20

B2

6D

01

27

0R

C6

50

08

02F0

5R

26

FC

3D

05

20

F2

01

01

39

3C

13

10

27

0C

39

0300

OF

33

CE

04

00

BD

EG

7E

DE

33

39

CE

04

06

BD

E0

0310

7E

7E

17

30

B0

El

RC

1 1

27

09

31

00

27

05

R7

00

0320

03

20

FI

39

96

40

81

23

27

16

81

5R

27

0C

81

42

0330

26

67

C6

20

08

5fl

26

FC

20

06

C6

4R

03

5R

26

FC

0340

08

R6

00

91

41

26

25

DF

3fl

DF

3C:

CE

00

41

DF

3E

0350

DE

3C

R6

00

03

DF

3C

DE

3E

E6

00

08

DF

3E

11

26

0360

09

9C

36

26

EB

DE

3R

C6

01

39

DE

3fl

08

R6

00

31

0370

00

26

F9

60

01

26

RD

C6

00

39

C:E

00

40

BD

EG

CC

0380

BD

El

RC

16

R7

00

08

30

SB

DF

36

39

30

EC

CE

05

0390

00

B0

03

00

SD

8E

5D

26

03

7E

00

RD

09

R6

00

81

03R0

00

26

F9

BD

01

9F

6D

01

27

EF

SC

13

10

26

E5

20

03B0

E8

B0

03

7R

CE

05

00

BD

03

24

5D

26

02

20

DR

09

03C0

R6

00

81

00

26

F9

BD

03

00

CE

04

DD

BD

E0

7E

DE

0300

38

BD

01

9F

BD

El

RC

81

59

27

0B

6D

01

27

Bfi

SC

03E0

13

10

26

D3

20

B3

09

R6

00

81

00

26

F9

36

5B

R7

03F0

01

BD.

01

DE

C6

50

08

6F

00

5R

26

FR

20

9B

01

01

0400

00

0R

00

00

00

04

00

0R

00

00

00

4D

45

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04

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i/ 0 Reader Service index— page 241

Microcomputing, October 1980 47

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VIDEO TERMINALS

NEW EMULATOR (Intertec), List $895$ 729

INTERTUBE II, List $995 ONLY $ 799

SOROC 120, List $995 SPECIAL $ 729

1Q140, List $1495 SPECIAL $1149

PERKIN-ELMER 550, List $997 $ 799

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HAZELTINE 1410, List $900 $ 749

1420 $ 849

1500, List $1225 $ 879

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1520, List $1650 $1389

ADDS R-20, List $995 $ 945

LEAR SIEGLER ADM3A, Assembled . . $ 849

TELEVIDEO 912C, List $950 $ 789

920C, List $1030 $ 849

PRINTERS

ANADEX DP-8000 $ 849

DP-9500, List $1650 $1399

INTEGRAL DATA IP-125 w/1210 $ 724

IP-225 w/ 1210 8- 1250 op., List $988 . . . $ 834
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NEC Spinwriters Call for Price

TELETYPE 43 KSR $1087

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730-1 parallel interface .... NEW LOW $679
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779 w/Tractor, List $1350 $1049

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parallel interface, List $1940 $1735

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RS232 Serial Interface $ 89

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SD COMPUTER VDB-8024,kit,List $370 $319t

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ESCON CONVERSION
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Parallel (TRS-80, Sorcerer, etc.), $575 $514

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TRS-80 Cable 25

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MEMORY BOARDS

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NORTH STAR 16K Dynamic RAM Board,

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CROMEMCO 16KZ-W, List $495 $419

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DM6400 64K Board w/all 64K, $795 . . . $659

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16K, 4 MHz or 2 MHz, List $349 $299

32K, 4 MHz, List $699 $629

16K Memory Master, List $399 $339

24K Memory Master, List $549 $465

INTERSYSTEMS (formerly Ithaca Audio)

8K Static 2 MHz, A&T, List $165 $149

8K Static 4 MHz, A&T, List $195 $176

16K Static 2 MHz, A&T, List $475 $427

16K Static 4 MHz, A&T, List $495 $445

64K Dynamic, List $995 $895

CALIFORNIA COMPUTER
16K Static, A&T, List $349.95 $259

FLOPPY DISK
CONTROLLER BOARDS

NORTH STAR, DD, Kit, List $399 $329

Assembled, List $499 $399

MORROW Disk Jockey 1, A&T ($213) . $189

Disk Jockey 2D, A&T, List $479 $429

SD Versafloppy 1, Kit, List $250 $212 t

Versaf loppy II, DD Kit, List $350 $297 t

Versafloppy II, DD, A&T, List $430 .... $365 t

DELTA double density A&T ($385) $345

CONDUCTOR, double density A&T . . . $269
INTERSYSTEMS FDC-2, A&T, $495 . . . $439
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TARBELL Floppy Disk Interface Kit ... . $199
double density, A&T, List $495 $444

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- WRITE FOR FREE CATALOG -

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Upgrading the Heath H8
With a Z-80 Microprocessor

Now that Heath has boarded the Z-80 bandwagon, keep in step with the HZ8 adapter.

Patrick Swayne
290 Springdale
Sebastopol, CA 95472

W hen the Heath Company decided to
get into the hobby computer
business, the 8080 was the most popular
micro, and thus the most logical choice for
their CPU. But the Z-80 has since eclipsed it
in popularity, and now Heath has joined the

parade by introducing their own Z-80-based
machine, the H89. This computer uses the
same disk and cassette operating systems
as the H8. Currently, the only software
available for it is 8080 software, but sooner
or later software will appear that takes ad-
vantage of the Z-80’s expanded instruction
set. Over 15,000 H8 owners may be left
behind as a result.

Photo 1 shows my solution to this prob-
lem. It is a Z-80 adapter that mounts piggy-
back onto the H8 CPU board. It plugs into
the sockets normally occupied by the 8080
CPU, the 8238 (or 74S438) system controller
and the 8224 clock driver. No modifications
are required on the CPU board itself, and at
any time you can remove the adapter and
replace the original ICs. It can be built for
about $30 to $40, including the Z-80 (which
has dropped to less than $15 at some mail-
order houses).

How the Adapter Works

The schematic of the adapter is shown in
Fig. 1. In this circuit, the original CPU and
system controller are replaced by a Z-80, six
commonly available TTL chips, a capacitor
and some resistors. (Two of the TTLs and
the capacitor may be eliminated if the op-
tional section is not built.) The clock driver
is also shown because some connections
were made to it. (A socket for the clock
driver was included in the actual assembly
to make these connections possible, even
though it is still electrically on the CPU
board.)

This circuit effectively emulates all of the
signals normally produced by the 8080 and
8238 that are used by the H8. This is easy to
accomplish because Heath chose to use
the fully decoded 8238 system controller
signals, rather than the undecoded status
or control signals (except Ml) that are
multiplexed onto the data bus of the 8080.

You can produce those signals by simply
ANDing together the appropriate Z-80 out-
puts. For example, the MEMR (memory

Photo 1. H8 CPU board with the adapter plugged in. The Z-80 (D780C) and some TTL ICs re-
piace-the original 8080 and 8238. / placed two extra ICs for the optional section, which I de-
signed after I took this photo, in the lower-left corner of the perf board. The Textool socket
to the left of the adapter is for testing homemade ROM monitors.

50 Microcomputing, October 1980

read) signal is produced by ANDing the
MREQ (memory request) and RD (read)
outputs. The NOR gates on the schematic
are used as negative AND gates in this ap-
plication (except those used as inverters).

Noninverting OR gates (such as the
74LS32) could have been used, eliminating
the need for inverters at the outputs of the
NORs, but the chip count would not have
been reduced, since the circuit requires at
least five ORs and seven inverters. I chose
to use 74LS02s because they are more
readily available. Pull-up resistors are re-
quired at each of the four memory and I/O
control outputs of the Z-80, because they
are Tri-state and might, at some time, be
undefined.

Deriving the 8238-type memory and I/O
control signals was easy, but some of the
others are not so obvious. The INTA (inter-
rupt acknowledge) signal is derived by AND-
ing the IORQ (I/O request) and Ml (first
machine cycle) outputs. The H8 uses an Ml
signal and decodes it by ANDing the 8080’s
PD 5 and SYNC outputs. Since the Z-80
already has an MT output, I simply ran it
(through an inverter) to the SYNC input of
the 8224 and tied PD 5 (actually, D 5 on the
8238) high through a resistor.

The WATT input on the Z-80 is the same as
the READY input on the 8080, except that it

does not have to be timed, so I connected
the raw RDYIN input at the 8224 to the Z-80
WAIT input. The Z-80 InT, BUSRQ and
BUSAK signals are just inverted counter-
parts of the 8080 INT, HOLD and HLDApins,
so I connected them together through in-
verters. The NMI (non-maskable interrupt)
on the Z-80 is not used, so I tied it high.
(Later on, I may write a monitor that uses
that interrupt to return to monitor control
from a user program, which would make
possible debugging a program that had in-
terrupts disabled.)

The HALT and RFSH outputs of the Z-80
are not needed, and were left unconnected.
The address pins on the Z-80 were con-
nected to the corresponding pins on the
8080 socket, and the data pins go to the DB
pins on the 8238 socket.

The Z-80 does not produce a counterpart
to the 8080 INTE (interrupt enable flip-flop)
output. The H8 uses that signal to light an
LED on the front panel and to operate the
single instruction (SI) button. INTE is pro-
duced by the optional section of the circuit,
and non-machine-language hackers who
never use the SI button may leave that sec-
tion out and tie pin 16 on the 8080 socket
high instead. If you do that, the SI button
will do nothing, and the ION light will
always be on.

The INTE output of the 8080 is set or reset
according to whether interrupts are en-
abled or disabled. Interrupts may be en-
abled and disabled by software, using the
El and Dl instructions, and are always dis-
abled when the processor receives an inter-
rupt. The HZ8 adapter circuitry responds
only to El and Dl, but that is sufficient to
achieve normal operation of the H8. It does
this by examining the data bus at Ml time,
when op codes are fetched.

The El instruction in binary is 11111011,
and Dl is 11110011. Bit 3, the only one that
changes, goes to the data input of a D-type
flip-flop, while the others, along with Ml,
are used to clock the data through when
they are all present. Capacitor C ^ slows the
clocking down just enough to ensure that
D 3 has settled down before it is sampled.

Single Stepping

Before I designed the INTE circuitry on
the adapter, I looked into various software
single-step schemes, which I considered
using, and found that they are all deficient
in some way. Most cannot handle certain in-
structions, and all require considerably
more code than the Heath method. The H8
can single-step through all of the 8080’s in-
structions, and, with my adapter, through
all of the Z-80’s codes in only a few bytes of

Fig. 1. Z-80 adapter circuit Connect the points marked “X”; don’t tie INTE (pin 16) on the 8080 socket high if optional section isn’t built.

Microcomputing, October 1980 51

, 'V

Photo 2. Side view of adapter board shows the frameless socket framed socket (left) for alignment. If pins remain at full length,

pins attached to the ends of the wire-wrap pins, using an ordinary the CPU card won’t fit in the first motherboard position.

code.

When you press the SI on the H8 front
panel, the monitor jumps to a routine that
first disables interrupts, bringing the INTE
output low. Then data is written to a port
which causes the output of a flip-flop to go
high. This signal goes to a NAND gate, the
output of which will produce a level 2 inter-
rupt when its other input goes high. That in-
put is controlled by two flip-flops whose
data is the INTE signal, with Ml used as the
clock. It takes two Mis to clock the current
value of INTE to the NAND gate.

After writing to the port mentioned
above, the software restores all user
registers and flags (previously saved when
entering the monitor mode). It then enables
interrupts, bringing INTE high, and jumps to
the user program. That jump sends out one
Ml pulse, and the first user instruction
sends out another, allowing the INTE signal
to generate an interrupt. The processor
allows the current instruction to finish, and
then control is returned to the monitor. In
this way, one user program instruction is
executed each time you press the SI button.

The single phase system clock required
by the Z-80 is a special case. It could be sup-
plied by the 02 (TTL) output of the 8224, ex-
cept that it requires a greater voltage swing
than TTL. The signal must go from a low of
no more than 0.8 volts to a high of no less
than 4.4 volts (with a 5 volt supply). I solved
this problem by running the clock through
two gates of a 7405 open collector inverter,
with pull-up resistors on the outputs.

To ensure a fast rise-time to the higher-
than-normal voltage, a 330-ohm resistor

52 Microcomputing, October 1980

pulls up the input to the Z-80. Another gate
of the 7405 is used to invert the 8224 RESET
to supply the Z-80’s inverted version of the
signal, and the rest are used in the optional
section.

Construction

Using the wire-wrap technique, I built the

adapter on a 3 x 4 inch piece of standard
perfboard with 0.1 inch spaced holes. I
placed 40-pin, 28-pin and 16-pin wire-wrap
sockets on the boards so that their pins are
directly over the holes in the 8080, 8238 and
8224 sockets in the CPU board. The Heath-
supplied X-ray view of the PC board can be
used to align the sockets. Another 40-pin

ICs

Qty.

Type

Function

2

74LS02

Quad 2-Input NOR

1

74LS04

Hex Inverter

1

74LS30

8-Input NAND*

1

74LS74

Dual D-type Flip-Flop*

1

7405

Hex Open Collector Inverter

1

Z80

Microprocessor

‘Optional

Sockets

Qty.

Pins

Augat Part No.

6(4)

14 WW

514-AG10F

2

16 WW

516-AG10F

1

28 WW

528-AG10F

2

40 WW

540-AG10F

1

16 F

716-AG4D

1

28 F

728-AG4D

1

40 F

740-AG4D

WW = Wire Wrap F = Frameless

16-, 28-, and 40-pin standard or wire-wrap sockets are also temporarily required to
mount frameless socket pins.

Miscellaneous

1 Dale No. LDP16-02-102G resistor pack or equivalent
or

12 Ik ohm resistors and 1 330 ohm resistor

3x4 inch perfboard

Wire

Table 1. HZ8 parts list. I built the prototype using 16-pin sockets for 14-pin ICs due tc
availability (or lack thereof).

wire-wrap socket, which holds the Z-80, was
installed between the other 40-pin and
28-pin sockets. Placement of the other
sockets is not important, but wire lengths
should be kept short.

Power and ground for the TTL were de-
rived from the VCC and ground pins of the
8238 socket, except for the 7405, which gets
its ground and power from the 8224 socket.
The two extra chips for the optional section
were added later, and get their power from
the Z-80 socket. For the pull-up resistors, I
used a resistor package containing 15 resis-
tors, all Ik ohm, connected internally to a
common pin. To make the 330 ohm resistor,
three resistors in the package were paral-
leled. Discrete resistors may also be used.

After being wired, the circuit should be
checked with an ohmmeter or continuity
tester for correctness, because when it is
finished it will be difficult to make changes.
To make it possible to plug the adapter into
the CPU board, frameless socket pins were
soldered to the ends of the wire-wrap pins
on the 8080, 8238 and 8224 sockets. Frame-
less sockets are socket pins that are in-
stalled on an aluminum frame that is re-
moved after the sockets are soldered into a
PC board.

To connect these pins to a wire-wrap
socket, they should first be removed from
the frame and plugged into an ordinary
framed socket. That will hold them in place
while they are soldered to the wire-wrap
pins.

Photo 2 shows how the pins are connect-
ed. If the wire-wrap pins are left their full
length, the CPU card with the adapter in-
stalled will not fit in the first motherboard
position. If the wire-wrapping is kept close
to the board, and all pins are cut so that
they protrude no more than 1/4 inch from
the perfboard (before the frameless pins are
attached), then the board will just fit in the
first slot.

Those H8ers capable of making their own
PC boards and using that technique would
not have a thickness problem. The frame-
less socket pins could be soldered directly
to the back of the PC board over the pro-
truding pins of the sockets.

Installation and Checkout

The adapter cannot be plugged into the
CPU board unless the 8080, 8238 and 8224
sockets on the board are all of the flat, low-
profile type. If any are not, they will have to
be changed. The 8080 and 8238 ICs should
be stored in anti-static material (foil will do)
while they are not in use.

After the TTL ICs, resistor pack and 8224
are installed, the adapter can be plugged in-
to the CPU board. If the CPU is to be used in
the second motherboard slot, framed
sockets can be plugged onto the socket
pins to protect them before the adapter
board is plugged in. Then the Z-80 can be in-

stalled, and the CPU board replaced in the
computer.

Checkout is simply a matter of turning
the computer on. If PAM-8 (the front-panel
monitor) signs on normally by lighting the
displays and beeping the horn, everything
else should also run normally. If there is
trouble, the first area to check is the wiring
and then the chips.

The Z-80

The 8080 instruction set consists of 244
individual op codes. Like most 8-bit pro-
cessors, each op code consists of one byte,
making 256 the total number of codes
possible. The Z-80, however, uses four of
the 12 op codes not used by the 8080 as the
first byte of several two-byte op codes. You
can think of these as 16-bit op codes that
are fetched one byte at a time. In that sense,
the Z-80 is a predecessor of the Intel 8088, a
16-bit micro designed to use an 8-bit data
bus.

The two-byte op codes are used for a
variety of purposes, including 16-bit
arithmetic, bit manipulation, working with
two index registers and some versatile
block move and search instructions. These
last types are an elementary form of
microcode, another way in which the Z-80
looks forward to the big machines.

Two of the Z-80’s 16-bit instructions
adversely affect the operation of the op-
tional section of the adapter circuit during
normal running (but not during single step-
ping). The second bytes of these instruc-
tions, SET 6,E and SET 7,E, have the same
binary code as Dl and El. Since the Z-80
issues an Ml pulse for each byte of two-

byte op codes, the adapter circuitry sees
the second bytes of those SET instructions
as Dl and El. The result is that the front
panel ION light may be lying if those in-
structions are in the code. Upon return to
monitor, however, an El instruction is en-
countered, and proper indication is
restored.

The Z-80 uses five of the other eight un-
used 8080 op codes for an unconditional
and four conditional relative jumps. In the
8080, all jumps require three bytes - one for
the op code and two for the address. With
the Z-80 relative jumps, a single byte follow-
ing the op code specifies the jump destina-
tion as a signed 8-bit offset added to the
program counter.

Another of the unused 8080 codes is a
special relative jump instruction that
decrements the B register each time it is ex-
ecuted and jumps if B is greater than zero.
The remaining two extra op codes are used
to switch between alternate sets of the six
general-purpose registers and alternate
flag registers and accumulators. In all, the
Z-80 has about 700 op codes in its instruc-
tion set.

A Final Note

Those who use Heath’s cassette assem-
bler, HASL-8 version 4.01.01 or 4.02.00, will
have to make a patch before it will work on a
Z-80. The program contains one of the
8080’s unused op codes, 40 (octal), which is
one of the Z-80’s relative jumps. To correct
this bug in version 4.01.01, change the con-
tents of address 055.265 (split octal) to 000.
To correct version 4.02.00, change 055.365
to 000. ■

Microcomputing, October 1980 53

The Age of Affordable Pers

single board at a cost of under $300. The Superboard II received rave
reviews by microcomputer experts such as:

"We can heartily recommend the Superboard II computer system for
the beginner who wants to get into microcomputers with a minimum of
cost. Moreover, this is a 'real' computer with full expandability."

POPULAR ELECTRONICS MARCH, 1979

"The Superboard II weighs in at $279 and provides a remarkable
amount of computing for this incredible price"

KILOBAUD MICROCOMPUTING FEBRUARY, 1979

"The Superboard II and its fully dressed companion the Challenger IP
series incorporate all the fundamental necessities of a personal com-
puter at a very attractive price. With the expansion capabilities
provided, this series becomes a very formidable competitor in the home
computer area" INTERFACE AGE APRIL, 1979

"The graphics available permit some really dramatic effects and are
relatively simple to program . . .The fact that the system can be easily
expanded to include a floppy means that while you are starting out with
a low-cost minimal system, you don't have to throw it away when you
are ready to go on to more complex computer functions. At $279,
Superboard II is a tough act to follow" RADIO ELECTRONICS JUNE, 1979

"The Superboard is an excellent choice for the personal computer
enthusiast on a budget'.' BYTE MAY, 1979

Since the introduction of Super-
board II, the cost of personal com-
puters has actually gone up with
new models by major manufacturers
ranging from $1000 to well over
$4000 due to the general cost of
inflation and the increasing func-
tionality included in these com-
puters. Today Cleveland Consumer
Computers is offering you the orig-
inal Superboard II at its original
price of just $279. In today's
economy this is by far the best buy

in personal computing ever!

The Superboard II can entertain
your whole family with spectacular
video games and cartoons, made
possible by its ultra high resolution
graphics and super fast BASIC. It
can help you with your personal
finances and budget planning,
made possible by its decimal
arithmetic ability and cassette data
storage capabilities. It can assist you
in school or industry as an ultra

powerful scientific calculator, made
possible by its advanced scientific
math functions and built-in
"immediate" mode which allows
complex problem solving without
programming! This computer can
actually entertain your children
while it educates them in topics
ranging from naming the Presidents
of the United States to tutoring
trigonometry — all possible by its
fast extended BASIC, graphics and
data storage ability.

The machine can be economically
expanded to assist in your business,
remotely control your home, com-
municate with other computers
and perform many other tasks via
the broadest line of expansion
accessories in the microcomputer
industry.

This machine is super easy to use
because it communicates naturally
in BASIC, an English-like program-
ming language. So you can easily
instruct it or program it to do
whatever you want, but you don't
have to. You don't because it comes
with a complete software library on
cassette including programs for
each application stated above. Ohio
Scientific also offers you hundreds
of inexpensive programs on ready-
to-run cassettes. Program it yourself
or just enjoy it; the choice is yours.

The Superboard II comes fully
assembled and tested. It requires
+ 5V at 3 Amps and a video monitor
or TV with RF converter to be up
and running. $279.00

Standard Features:

• Uses the ultra powerful 6502
Microprocessor.

• 8K Microsoft BASIC-in-ROM.
Full feature BASIC runs faster
than currently available personal
computers and all 8080 based
business computers.

• 4K static RAM on board expand-
able to 8K.

• Full 53-key keyboard with
upper/lower case and user
programmability.

• Kansas City standard audio
cassette interface for high
reliability.

• Full machine code monitor and
I/O utilities in ROM.

54 Microcomputing, October 1980

final Computing is Still Here.

Direct access video display has IK
of dedicated memory (besides 4K
user memory), features upper
case, lower case, graphics and
gaming characters for an effective
screen resolution of up to 256 x
256 points. Normal TVs with
overscan display about 24 rows of
24 characters without overscan up
to 30 x 30 characters.

Optional Extras:

• Available 610 expander board
features up to 24K static RAM
(additional), dual mini-floppy
interface, and an OSI 48 line
expansion interface.

• Assembler/Editor and Extended
Machine Code monitor available.

• 630 I/O Expander.

RGB color and NTSC composite
color outputs with up to 16 colors,
Dual 8-axis joystick interface, AC
remote control interface which
mates with AC-12P, home security
interface which mates with the
AC-17P, 16-line parallel I/O inter-
face, 16-pin I/O bus interface
which allows the connection of
parallel I/O lines or high speed
analog I/O module, or a PROM
blaster or solderless interface pro-
totyping board, programmable
sound generator and program
selectable modem and high speed
printer ports, and more.

Freight Policies All orders of $100 or more
are shipped freight prepaid. Orders of less
than $100 please add $4.00 to cover shipping
costs. Ohio Residents add 5.5% Sales Tax.

Guaranteed Shipment Cleveland
Consumer Computers & Components
guarantees shipment of computer systems
within 48 hours upon receipt of your order.

Our failure to ship within 48 hours entitles
you to $35 of software, FREE.

Hours:

Call Monday thru Friday
8:00 AM to 5:00 PME.D.T.

Software:

Ohio Scientific and independent suppliers
offer hundreds of programs for the
Superboard II, in cassette and mini -floppy
form. Here is a sampling of popular Ohio
Scientific programs for the Superboard II.

CS-600

EDUCATIONAL PROGRAMS

SBII&CIP

Price

BASIC Tutor Series

SCE-336

$35.00

Clock Tutor

SCE-353

6.50

Continents Quiz

SCE-332

6.50

Definite Integral

SCE-326

6.50

French Drill & Tutor

SCE-339

6.50

German Tutor & Drill

SCE-342

6.50

Hangman (8K)

SCE-324

9.00

Log Tutors 1-3

SCE-344

6.50

Math Blitz

SCE-329

6.50

Math Intro

SCE-319

6.50

Mathink

SCE-337

9.00

Matrix Tutors 1-3

SCE-345

6.50

Metric Tutor & Quiz

SCE 335

6.50

Spanish Drill & Tutor

SCE-352

6.50

Spelling Quiz

SCE-333

6.50

Trig Tutor (8K) I & II

SCE-318

6.50

BUSINESS PROGRAMS

Address Book

SCB-523

9.00

Advertisement Demo

SCB-520

6.50

Inventory Demo

SCB-518

6.50

Mailing List (8K)

SCB-524

6.50

Straight & Constant Depreciation

SCB-500

9.00

Time Calculator

SCB-525

9.00

PERSONAL PROGRAMS

Biorhythm

SCP-716

9.00

Calorie Counter

SCP-708

6.50

Checking Account

SCP-719

9.00

Loan Finance

SCP-717

6.50

Personal Calendar

SCP-718

6.50

Savings Account

SCP-720

9.00

GAME PROGRAMS

Baseball I

SCG-975

6.50

Black Jack

SCG-955

6.50

Civil War

SCG-977

6.50

Destroyer

SCG-951

6.50

High Noon

SCG-960

6.50

Hockey

SCG-979

6.50

Lander

SCG-925

6.50

New York Taxi

SCG-956

6.50

Poker

SCG-962

6.50

Racer

SCG-949

6.50

Space War

SCG-942

6.50

Star Trek

SCG-946

6.50

Star Wars

SCG-926

6.50

Tic-Tac-Toe

SCG-945

6.50

Tiger Tank

SCG-950

14.00

"\ir t-.^fTTri

w m ■ m

610 Board

Z m *-0

»o ^ m O i

To Order

Or to get our free

Hardware:

Superboard II

as specified in the advertisement . $279

610 Board For use with Superboard II and
Challenger IP, 8K static RAM ex-
pandable to 24K or 32K system total.
Accepts up to two mini-floppy disk
drives. Requires + 5 V@ 4.5 amps. 298
Mini-Floppy Disk Drive

Includes Ohio Scientific's PICO
DOS software and connector cable.
Compatible with 610 expander
board. Requires + 12V@ 1.5 amps

and +5V@ 0.7 amps.

299

630 Board As specified in the advertisement .

229

AC-3P

12" combination black and white
TV/video monitor.

159

4KP

4K RAM chip set.

79

PS-005

5V 4.5 amp power supply for
Superboard II.

35

PS-003

Mini -floppy power supply.

29

C1P Sams

ClP/Superboard II Manual.

8

OS-65D

V3.2 Disk Operating System with
9-digit extended BASIC, random
access and sequential files.

49

CS-600

Metal case for Superboard II, 610
and 630 board and two power
supplies.

49

CS-610

Metal case for single floppy disk
drive and power supply.

49

AC-12P

Wireless AC remote control system.
Includes control console, two lamp
modules and two appliance

modules for use with 630 board.

175

AC-17P

Home security system. Includes
console, fire detector, window

protection devices and door unit for
use with 630 board.

249

C4P Sams C4P Manual .

16

C3 Sams

Challenger III Manual.

40

Charge your order to your VISA or MASTER CHARGE ACCOUNT
Ohio Residents Call: (216) 464-8047. Or write, including your check
or money order, to the address listed below.

ft CLEVELAND CONSUMER 28
Gi|j COMPUTERS & COMPONENTS

P.O. Box 46627
Cleveland, Ohio 44146

Order Form:

CLEVELAND CONSUMER P.O. Box 46627

COMPUTERS & COMPONENTS Cleveland, Ohio 44146

□ Superboard II $279. □ 630 Board $229.

□ 610 Board $298. □ AC-3P 12" B-W Monitor $159.

□ Mini-Floppy Disk Drive $299. OOP Sams Manual $8.

(Attach separate sheet for other items.)

NAME:

ADDRESS :

CITY:

STATE:

_ZIP:_

Payment by: VISA: _ MASTER CHARGE: _ MONEY ORDER:

Credit Card Account jf

Expires: Interbank § (Master Charge)

TOTAL CHARGED OR ENCLOSED: $ (Ohio Residents add 5.5% Sales Tax)

All orders shipped insured UPS unless otherwise requested. FOB Cleveland, Ohio.

Reader Service index— page 241

Microcomputing , October 1980 55

Robert M. Richardson
Drawer 1065

Chautauqua Lake, NY 14722

Level II ROM

Subroutine Test

Talk to your TRS-80 in its own language.

Function

Number Type

Decimal

Hexadecimal

ABS

2-4-8

2423

0977

ATN

4-8

5565

15BD

BASIC

(Return L-ll)

6681

1A19

BASIC

(Return disk)

112

0075

BREAK

(RST address)

16396

400C

CDBL

2-4

2779

0ADB

CINT

4-8

2687

0A7F

CLS

2-4-8

457

01 C9

COS

4-8

5441

1541

CSNG

2-8

2737

0AB1

EXP

4-8

5177

1439

FIX

2-4

2854

0B26

INT

2

2871

0B37

INVERT SIGN

2

3153

0C51

INVERT SIGN

4-8

2434

0982

LOG

4-8

2057

0809

MEMORY

(Size input)

181

00 B 5

RANDOM

2-4-8

467

01 D3

RETURN

(T o subroutine)

32000

7D00

RND <1.0

4-8

5321

14C9

SGN

2

2442

098A

SIN

4-8

5447

1547

SQR

4-8

5095

13E7

TAN

4-8

5544

15A8

Table 1. Level II arithmetic/trigonometric conversion table. Number types: 2 = inte-
ger; 4 = single precision; 8 = double precision.

Listing 1. Source code.

00100

W4UCH

EQU

7D00H

00110

ORG

W4UCH

00120

LD

A , 4EH

00130

CALL

0 3 2 AH

00140

CALL

1BB3H

00150

RST

1 OH

00160

CALL

0E6CH

00170

RETURN

EX

AF, AF

; 7D00H = 32000 DECIMAL
; PROGRAM WILL START HERE
;4EH="N"=NUMBER DESIRED ?
; DISPLAY "N" ON VIDEO
; KYBD/VIDEO INPUT ROUTINE
; SCAN STRING - SET C FLAG
; ASC I I “ACCUM RET MINIMUM
; EXCHANGE REGISTERS -

H ere is another interesting test program
for the advanced assembly-language
programmer. It lets you access and test
many of the arithmetic/trigonometric sub-
routines in the TRS-80 Level II ROM written
by Microsoft’s Bill Gates and Paul Allen.

The beginning assembly-language pro-
grammer should certainly learn how to
write fundamental arithmetic/trig functions
by himself, but once these techniques have
been mastered as part of the learning pro-
cess, it is inefficient and unnecessary to du-
plicate in assembly language those subrou-
tines already in the Level II ROM.

Table 1 lists those functions and their ad-
dresses that may be accessed and tested
by this mini-program that only occupies 144
bytes of high memory and may be entered
using the TRS-80 Editor/Assembler in about
five minutes.

Listing 1 is a printout of the test
program’s source code, and Listing 2 shows
the program’s object code. As you will see,
the majority of this program is written using
Level II ROM subroutines. Were these sub-
routines not used in this particular assem-
bly-language test program, it would require
ten times as much program memory and oc-
cupy 550 rather than 55 assembly-language
program lines.

Program Flow

The comments included with the source
code program are largely self-explanatory

56 Microcomputing, October 1980

and delineate each line’s function. This pro-
gram operates equally well with non-disk
Level II, DOS 2.1, DOS 2.2 and NEWDOS + .
Program operation is as follows:

1. Load the program under the SYSTEM
or DOS command. Give it any name you
wish. We like the program name DISCOV,
for discovery, since that is what the pro-
gram is all about. After loading is complete,
type in /32000 to activate the program (with
disk you must first load BASIC, then type
SYSTEM, ENTER, and then type in /32000
ENTER, if you load the program in DOS).

2. The letter ‘N?’ will appear on the video.
The program is asking you for a number to
work on. Enter any number up to 16 digits,
depending on the function you wish to test.
Let us start out with a simple example by
entering the number 100000.

3. The numbers ‘2’ ‘100000’ will appear on
the next line of the video display. The ‘2’ is
the number type brilliantly calculated by the
Level II ROM. Since we are dealing only with
numbers in this article, we will skip over
strings et al for the time being. The number
types are as follows: 2 = integer, 4 = single
precision and 8 = double precision. Table 1
lists those operations that can be per-
formed on a number for a given number
type; e.g., it is against the rules to take the
square root SQR of an integer. We must
first change it.

4. On the following line of the video dis-
play you will see ‘C?’. The program is asking
you what type of conversion you wish. Let’s
enter 2737, which is the address of the
CSNG function, to change our number from
an integer to single precision, then ENTER.
The next line will show ‘4’ ‘1000’. We now
have a single-precision number to work
with, so let’s try taking its square root by
typing in 5095, the address of the SQR rou-
tine, then ENTER. The next line shows ‘100’.
This sure is easier than writing a complete
stand-alone assembly-language square
root subroutine. Let’s try it again. Type in
5095 ENTER. Again, the line below displays
the square root, this time, the numeral 10.

5. To insert a new number to try your pro-
gram on, merely type in 32000 ENTER. This
brings us back to where we started by dis-
playing ‘N?’. Thus, 32000 is our subroutine.
Our assembly-language program does not
discriminate between ROM or RAM; it could
care less.

6. We could go on and on converting num-
bers such as deriving the natural LOG of
any number and then restoring it to its
original value via the EXP function, and/or
deriving the TANgent of a number, then its
arc tangent ATN and then the TANgent
again ... ad infinitum. You may escape this
conversion routine any time you wish by
typing 6681 ENTER, which will take you
back to BASIC with a READY displayed. To
return to your conversion routine, type SYS-

00180

EXX

00190

LD

DE ,411 DH

00200

LD

HL, STORE

00210

LD

B,8

00220

CALL

09D7H

00230

LD

DE,4127H

00240

LD

HL f CDBL

00250

LD

3, 8

00260

CALL

09D7H

00270

LD

A, (40AFH)

00280

LD

(FLAG) ,A

00290

ADD

A, 48

00300

CALL

0 32AH

00310

LD

A,20H

00320

CALL

0 3 2 AH

00330

CALL

0FBDH

00340

CALL

2 3A7H

00350

LD

A , 0 DII

00360

CALL

032H

00370

LD

A, 43H

00380

CALL

32AH

00390

CALL

1BB3H

00400

RST

1 OH

00410

CALL

0E6CH

00420

CALL

0A7FH

00430

LD

(CONV) , HL

00440

LD

DE ,CDBL

00450

LD

HL, 4 1 27H

00460

LD

B , 8

00470

CALL

09D7H

00480

LD

DE , STORE

00490

LD

HL , 4 1 1 DII

00500

LD

B , 8

00510

CALL

09D7H

00520

LD

A, (FLAG)

00530

LD

(40AFH) , A

00540

LD

IIL, RETURN

00550

PUSH

HL

00560

LD

HL, (CONV)

00570

PUSH

HL

00580

EX

AF , AF 1

00590

EXX

00600

RET

00610 FLAG

DEFS

1

00620 CONV

DEFS

2

00630 CDBL

DEFS

8

00640 STORE

DEFS

8

00650

END

W4UCH

TO PRESERVE VALUES.

MOVE MEM ACCUM DATA FROM
TO TEMPORARY STASH.
NUMBER OF BYTES TO MOVE
MOVE IT - SUBROUTINE
MOVE CDBL DATA FROM-
TO TEMPORARY STASH.
NUMBER OF BYTES TO MOVE
MOVE IT - SUBROUTINE
NUMBER TYPE MEM LOCATION
MOVE TO TEMPORARY STASH
CONVERT TO ASCII NUMBER
DISPLAY NUMBER TYPE
2 OH = ASCII SPACE
DISPLAY SPACE ON VIDEO
CONV MEM ACCUM TO ASCII $
DISPLAY CONVERTED NUMBER
0DH=SKIP A LINE/CARR RTN
DO IT - ON VIDEO DISPLAY
M C M = CONVERSION NUMBER?
DISPLAY "C" ON VIDEO
KYBD/VIDEO INPUT ROUTINE
SCAN STRING - SET C FLAG
ASCI I-ACCUM RET MINIMUM
CONVERT TO INTEGER
STORE CONVERSION ADDRESS
MOVE CDBL DATA FM STASH-
TO PERMANENT ADDRESS.
NUMBER OF 3YTES TO MOVE
MOVE IT - SUBROUTINE
MOVE MEM ACCUM FM STASII-
TO PERMANENT ADDRESS.
NUMBER OF BYTES TO MOVE
MOVE IT - SUBROUTINE
NUMBER TYPE FROM STASH-
TO PERMANENT ADDRESS.
RETURN MEM LOCATION-
LOADED INTO STACK.
CONVERSION MEM LOCATION-
LOAD ON TOP OF STACK.
RESTORE REGISTER5-
TO ORIGINAL VALUES.
SNEAKY CALL- TOP OF STACK
NUMBER TYPE STASH
CONVERSION ADDRESS STASH
CDBL DATA STASH
ACCUMULATOR STASH
AMATEUR RADIO CALL LTRS

Listing 2. Object code.

7D00

00100 W4UCII

EOU

7D00H

7D00

00110

ORG

W4UCH

7D00

3E4E

00120

LD

A , 4EII

7D02

CD2A03

00130

CALL

0 32 AH

7D05

CDB31B

00140

CALL

1BB3II

7D08

D7

00150

RST

1 OH

7D09

CD6C0E

00160

CALL

0E6CII

7D0C

08

00170 RETURN

EX

AF , AF*

7D0D

D9

00180

EXX

7D0E

111D41

00190

LD

DE , 4 1 1 DII

7D11

21837D

00200

LD

HL, STORE

7D14

0608

00210

LD

B , 8

7D16

CDD709

00220

CALL

09D7H

7D19

112741

00230

LD

DE , 4 1 27H

7D1C

217B7D

00240

LD

IIL, CDBL

7D1F

0608

00250

LD

B , 8

7D21

CDD709

00260

CALL

09D7H

7D24

3AAF40

00270

LD

A, (40AFH)

7D27

32787D

00280

LD

(FLAG) , A

7D2A

C630

00290

ADD

A, 48

7D2C

CD2A03

00300

CALL

032AH

7D2F

3E20

00310

LD

A, 20H

7D31

CD2A03

00320

CALL

032AH

7D34

CDBD0F

00330

CALL

0FBDH

7D37

CDA728

00340

CALL

2 8A7H

7D3A

3E0D

00350

LD

A, 0DH

7D3C

CD3200

00360

CALL

032H

7D3F

3E4 3

00370

LD

A , 4 3H

7D41

CD2A03

00380

CALL

3 2 AH

7D44

CDB31B

00390

CALL

1BB3H

7D47

D7

00400

RST

1 OH

7D48

CD6C0E

00410

CALL

0E6CH

Microcomputing, October 1980 57

7D4B

CD7F0A

00420

CALL

0A7FH

7D4E

22797D

00430

LD

(CONV) ,HL

7D5 1

117B7D

00440

LD

DE,CDBL

7D54

212741

00450

LD

IIL, 4127H

7D57

0608

00460

LD

B , 8

7D59

CDD709

00470

CALL

09D7II

7D5C

1 1837D

00480

LD

DE, STORE

7D5F

211D41

00490

LD

IiL , 4 1 1 DH

7D62

0608

00500

LD

B,8

7D64

CDD709

00510

CALL

09D7H

7D67

3A787D

00320

LD

A, (FLAG)

7D6A

32AF40

00530

LD

(40AFH) ,A

7D6D

210C7D

00540

LD

HL , RETURN

7D70

E5

00550

PUSH

HL

7D71

2A797D

00560

LD

HL, (CONV)

7D74

E5

00570

PUSH

HL

7D75

08

00580

EX

AF , AF 1

7D76

D9

00590

EXX

7D77

C9

00600

RET

0001

00610 FLAG

DEFS

1

0002

00620 CONV

DEFS

2

0008

00630 CDBL

DEFS

8

0008

00640 STORE

DEFS

8

7D00

00650

END

W4UCH

00000

TOTAL

ERRORS

TEM, then ENTER and type /32000, then
ENTER.

Conclusion

This article covers only a few of the sub-
routines in Level II BASIC ROM. Assembly-
language programming is the ne plus ultra
of serious computing. Your assembly-lan-
guage program runs 300 times faster than
the same program in BASIC and uses only
1/10th as much memory.

Learning to talk to your computer in its
own language rather than through an inter-
preter (BASIC, FORTRAN or Pascal) is a
most satisfying and rewarding experience if
you have the patience and fortitude to
master it. ■

The material in this article comes from The Disassembled
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58 Microcomputing, October 1980

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i/ 0 Reader Service index— page 241

Microcomputing, October 1980 59

Expansions and Programming

Now that your computer is built, you’ll want to expand it
for more memory and I/O capability. . . and then on to programming.

Peter A. Stark

PO Box 209

Mt. Kisco, NY 10549

I ’ve described how to build tfte basic
Kilobaud Klassroom Komputer. This time
I’ll show some ways in which the computer
can be expanded and begin my discussion

of computer programming.

Though we did not originally intend our
computer to be anything but a small control
computer, a number of readers have asked
for expansion information so they could
make It into a more general-purpose sys-
tem.

With some of the expansions described
below, it is possible to run some programs
that people associate only with larger sys-

tems. (For example, a machine-language
monitor for entering, executing and debug-
ging machine-language programs, as well
as a Tiny BASIC, are available from Star-
Kits, PO Box 209, Mt. Kisco NY 10549.)

Installing a Second PIA

The printed circuit board layout I pre-
sented last time has one socket that is fully
wired for a PIA parallel interface chip, and a
second socket that can be used either for a
second 6820 (or 6821) PIA or for a 6850 ACIA
for serial communications.

This socket is located in the top right cor-
ner of the PC board (see Photo 1). Since the
PIA and ACIA connections are slightly dif-
ferent, only some of the pins of this socket
position are already connected (the data
bus and clock connections for the two ICs
are in the same relative positions). The oth-
er connections, however (those that are dif-
ferent for the two ICs), must be wired by
hand for the 1C you plan to use.

Installing a PIA is easy. Just wire the fol-
lowing pins:

• Pin 24, CS1, connects to + 5 volts. Pin 24
connects to a small round pad right next to
it; just next to that is another round pad,
which is at +5 volts. Connect a short jump-
er between them.

• Pin 34, RESET, connects to pin 34 of the
other PIA. Small round pads are located
next to pin 34 of both PIAs to make the con-
nection easier.

• Pin 35, RSI, connects to pin 35 of the
other PIA. Round pads located next to pin
35 of both PIAs are used.

In addition, both PIAs have small pads
next to pins 2 through 19 and pins 39 and 40;

Photo 1. This unit has been expanded with both the RS-232C serial port as well as an addi-
tional IK of RAM.

60 Microcomputing, October 1980

♦ 5V

♦5V

Fig. 1. RS-232C/TTL level conversion.

these pins are the data I/O ports that con-
nect to the outside world. (I will give much
more information regarding the PIA in a fu-
ture installment.)

Installing an ACIA

Installing an ACIA takes a little more
work, but is still useful. To take advantage
of the nine pins prewired for either a PIA or
an ACIA, the ACIA socket must be installed
so pin 1 of the ACIA goes in the hole that
would otherwise be used for pin 6 of the
PIA. When installed in this way, the data
bus and clock connections fit perfectly into
the connections already established for the
PIA.

The remaining ACIA pins must be con-
nected by hand as follows:

Pin 1 to ground.

Pins 2 and 6 are the serial data input and
output, respectively. Both of these are TTL-
compatible, whereas most serial I/O de-
vices will use either current loop or EIA RS-
232C connections. This means that we
must build an interface circuit that will con-
vert between the TTL voltage levels used by
the ACIA and either the voltage levels of an
RS-232C connection or the current levels of
a current loop connection. This interface
circuitry, which I discussed in Kilobaud
Klassroom No. 13 (October 1978, p. 46), can
be built in the wire-wrap area of the board.

Fig. 1 shows the level conversion circuits
needed to interface to an RS-232C terminal.
The top circuit converts the TTL output of
the ACIA to RS-232C levels of between -3
and - 15 volts for a 1, and between +3 and
+ 15 volts for a 0. It uses an inexpensive 741
op amp to provide the required inversion
and to provide positive and negative output
voltages. (Although a negative voltage sup-
ply is obviously needed to provide a
negative output, the current is negligible
and so a 9-volt transistor radio battery will
provide enough current for even extensive
testing and experimenting.)

The bottom circuit is used in the opposite

direction. Negative voltages from the RS-
232C port turn off the transistor and provide
a high level to the ACIA for a 1, while posi-
tive input voltages turn on the transistor
and provide an output near 0 volts for a 0.
Any inexpensive npn silicon transistor can
be used in this circuit.

Pins 3 and 4 require a clock pulse at a fre-
quency that is a multiple of the baud rate.
The clock frequency can be either the same
as the baud rate, 16 times the baud rate or
64 times the baud rate, depending on how
the ACIA is programmed. But most design-
ers, wishing to stay compatible with UARTs
that require a frequency of 16 times the
baud rate, use the same multiple with the
ACIA. For example, for transmission at 300
baud, a frequency of 4800 pulses per sec-
ond would be required.

Fig. 2 shows two common ways of gener-
ating this clock frequency. Fig. 2a uses a
555 timer 1C as an oscillator to provide a fre-
quency equal to 16 times the desired baud
rate. Since the circuit frequency is set by an
RC network, careful adjustment of potenti-
ometer R2 is required, and even then the fre-
quency may drift with time. But this circuit
is still popular because it is inexpensive
(though a frequency counter is needed for
adjustment).

Several baud rate generator ICs that gen-
erate the same frequencies by using a crys-
tal oscillator as a reference are available.
One popular device is the Motorola
MC14411. As shown in Fig. 2b, this circuit
uses a 1.8432 MHz crystal, which connects
directly to an on-chip oscillator to provide
the crystal-controlled reference. Inside the
14411 is a series of counters that divides
the crystal frequency to provide a number
of simultaneous baud rate output signals.
For example, the 300 baud rate output on
pin 7 comes from a counter that divides the
1.8432 MHz crystal frequency by 384 to pro-
duce exactly 4800 pulses per second; this is
equal to 16 times 300.

This circuit will provide almost any baud
rate we might need (including some not
shown in Fig. 2b), but it has the disadvan-
tage of requiring a $10 1C, as well as a $5
crystal. If we don’t need 110 baud, then the
circuit of Fig. 3 saves the price of the crystal
by using the computer’s own clock as the
crystal reference. (But this circuit will only
work if the 6802 is using a 3.579 MHz color
TV crystal for the clock.)

When a 3.579 MHz crystal is used as the
6802 clock, this frequency is divided by the
6802 to provide an Enable signal of 3.579/4
MHz, or .89475 MHz. This is just a little less
than half of 1.8432 MHz (about three per-
cent less, to be exact). If we send this signal
to pin 21 of the 14411 instead of the 1.8432
MHz signal that would normally be there
from the crystal, the 14411 will generate
outputs just slightly less than half the nor-

mal ones. For example, pin 7 will provide an
output of just under 1 50 baud, instead of the
normal 300 baud. So if we need 300 baud,
we simply move over to pin 5, which now
provides just under 300 baud instead of its
customary 600 baud. Although these baud
rate signals are about three percent low,
this is still within the normal tolerance of
serial terminals.

ACIA pins 8, 10 and 12 should be jump-
ered to + 5 volts. The most convenient loca-
tion is the hole that would otherwise go to
pin 22 of a PIA.

Pin 9, CS2, should be connected to pin
11 of the 74LS138 address decoder at the
small round pad next to it.

ACIA pin 11, RS, connects to address bit
A0 at the hole that would normally connect
to pin 36 of a PIA in that 1C position.

Pin 13, R/W, should be connected to
the hole that would otherwise go to pin 21 of
a PIA.

Finally, pins 23 and 24 should be ground-
ed to pin 1 of the PIA socket. (If, however, a
serial port with handshaking is needed,

BAUD RATE R! R2 C

NO 5.6K 5K O.I*F

300 22K 25K O.OifiF

1200 5.6K 5K O.OI*F

555

TIMER

T

16 x BAUD RATE CLOCK

a) 555 TIMER CIRCUIT

♦5V

HO

BAUD

300

BAUD

600

BAUD

1200

BAUD

2400

BAUD

4800

BAUD

9600

BAUD

b) MCI 44 II BAUD RATE GENERATOR

16 x BAUD RATE
> CLOCK -
CHOOSE ONE

Fig. 2. Two circuits for generating a 16x
baud rate clock for an ACIA.

150 BAUD
300 BAUD
600 BAUD
1200 BAUD
2400 BAUD
4800 BAUD

16 x

BAUD RATE
CLOCK -
CHOOSE ONE

Fig. 3. Alternate 16x baud rate clock genera-
tor.

Microcomputing, October 1980 61

-12V

741-4

5V

*PI A2-22 ACIA-10 ACIA-12 ACIA-8

MC14411 -22 MC14411-24 R4-1 R6-1

MC1441 1-10

741 +

741-3 R4-2 R5-1

741-

741-2 R3-2

7410UT

741-6 R8-1

8 V

741-7

A0

*PIA2-36 ACIA-11

ACI ASEL 7

*74LS138-11 ACIA-9

BAUDCLOCK

ACIA-3 ACIA-4 MC14411-3

EIA-IN

EIA-PIN-2 R7-2

EIA-OUT

EIA-PIN-3 R8-2

ENABLE

♦PIA2-25 MC1441 1-21

GROUND

♦PIA2-1 ACIA-1 ACIA-23 ACIA-24

MC14411-12 MCI 44 1 1 -23 Ql-E R5-2

CR2-2 El A-PIN-7

G1BASE

CR2-1 Ql-B R7-1

R/W 7

♦PIA2-21 ACIA-13

RXDATA

ACIA-2 Ql-C R6-2

TXDATA

ACIA-6 R3-1

Table 1. Wiring

list for adding an ACIA, baud rate generator and serial RS-232C port.

then pin 24, CTS, is used for that purpose.
When pin 24 is low, the ACIA will output;
when it is high, the ACIA will stop output-
ting and will wait.)

Table 1 is a wiring list that shows all the
connections needed to install a complete
serial port using the circuitry of Figs. 1 and
3. The connection points marked with a star
are existing points in the computer to which
you can connect to get the desired signal.
For example, address bit AO is listed as

AO * PIA2-36 ACIA-11

which means that AO is present on pin 36 of
the PI A2 socket and should be connected to

pin 11 of the ACIA.

Photo 1 shows how this addition mounts
on the printed circuit board. The 6850 ACIA
is in the top right corner, with the 14411
right under it. The eight-pin 1C under that is
the 741 op amp, and the rest of the RS-232C
interface is just to its left. In this case, the
25-pin RS-232C connector is on the other
end of a six-foot cable, but it could have
been attached to the edge of the board with
a hot-melt glue gun.

Adding 128 Bytes More RAM

The basic 128 bytes of RAM inside the

DATA BUS

ADDRESS

BUS

A 7
A8
A9
^ AIO
ENABLE

(OOOO- IFFF)
FROM ADDRESS
DECODER PIN 15

8

7

6

5

4

3

2

23

22

21

20

19

18

17

10

II

12

15

13

14

16

Fig. 4. 128-byte RAM addition.

6802 is enough for many applications, but
sometimes additional RAM is useful. There
are two easy ways to add a little more RAM.
The easiest — requiring just one 1C — adds
another 128 bytes of RAM using an
MCM6810 RAM for about $5 (Fig. 4). The wir-
ing list for adding this modification is

APPLE COMPUTER

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Apple II plus 32K

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Apple II Disk w/o Controller 495.00 489.00

Apple Pascal Language

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Apple Silentype Printer 595.00 529.00

Silentype Paper (Box of 10) 42.50 39.95

Integer Firmware Card 200.00 179.00

Centronics Parallel Printer

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High Speed Serial Card . . . 195.00 169.00

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Dos Tool Kit 75.00 65.00

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Apple Writer 75.00 85.00

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CORVUS

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Desktop Plan 99.50 79.00

CCA Data Management 99.50 79.00

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7440 Programmable

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7490 GPIB IEEE-488

Interface Card 300.00 259.00

7520 Extender Board 24.95 22.00

7710 Asynchronous Serial

Card 159.95 139.00

7712 Synchronous Serial

Card 159.95 139.00

7720 Parallel Printer

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7728 Centronics Parallel

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7811 Arithmetic Processor

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62 Microcomputing, October 1980

shown as Table 2.

No additional circuitry is needed since
this 1C has six chip select (CS) inputs. To
enable the 6810, CSO and CS3 must be high,
while CS1, CS2, CS4 and CS5
must be low. In this circuit, these chip se-
lects work like this:

CS4 connects to pin 15 of the 74LS138
address decoder (shown in Fig. 9 of the
June installment). This pin goes low only on
valid memory addresses beginning with 000
in bits A15, A14 and A13; this translates to
the entire range from 0000 to 1 FFF (in hexa-
decimal).

CSO, CS1, CS2 and CS5 connect to
address bits A7 through A10; together with
CS4, then, any memory address
such as

000x xOOO Ixxx xxxx

(where x stands for a don’t-care bit, which
could be either 0 or 1) will select this RAM
1C. If A12and All, the two don’t-care bits on
the left, are 00, the 6810 takes on addresses
from 0080 through 00FF, which is the 128
bytes just above the 128 bytes already in the
6802, giving us a total of 256 bytes from
0000 through 00FF. This is a useful address
range, since this first group of 256 locations
(called page 0) is especially easy and quick
to address in a 6800 or 6802 processor.

(Because of incomplete address decod-
ing, if those two don’t-care bits are nonzero,

this RAM also responds to addresses 0880,
1080 and 1880, but this doesn’t conflict with
any other address assignments.)

Finally, CS3 connects to the Enable sig-
nal coming from the 6802. This is a timing
signal that makes sure that the 6810 is
selected only when valid data actually ex-
ists on the data bus. As shown in the wave-
forms in the June installment, data is pres-
ent on the data bus at the end of the E sig-
nal and should normally be grabbed off the
bus at that time.

When data is coming from the outside
back to the 6802, the processor does this
automatically; but whenever data is being
sent from the 6802 out to some other device
such as a memory 1C or I/O device, then this
device must be told when to get the data.
This is why it wasn’t necessary to send the
E signal to the 2716 EPROM (which never
gets any data from the data bus), but has to
be sent to the PIA, ACIA and all RAM.

Adding IK More RAM

A slightly more ambitious project is to
add an entire IK of RAM with just three
chips, using the circuit of Fig. 5 for a total
cost of about $15. These three ICs are
shown in Photo 1, just to the left of the
14411 baud rate generator.

The 74LS138, labeled SEL2 in Fig. 5, is an
additional address decoder (not the same

5U

6810-24

A0

♦6802-9

6810-23

A1

*6802-10

6810-22

A2

*6802-11

6810-21

A3

*6802-12

6810-20

A4

*6802-13

6810-19

A5

*6802-14

6810-18

A6

*6802-15

6810-17

A7

*6802-16

6810-10

A8

*6802-17

6810-11

A9

*6802-18

6810-12

A10

*6802-19

6810-15

ADDROOOO '

*74LS138-

15 6810-

DO

*6802-33

6810-2

D1

*6802-32

6810-3

D2

*6802-31

6810-4

D3

*6802-30

6810-5

D4

*6802-29

6810-6

D5

*6802-28

6810-7

D6

*6802-27

6810-8

D7

*6802-26

6810-?

ENABLE

*6802-37

6810-13

GROUND

6810-1

R/W '

*6802-34

6810-16

Table 2. Wiring list for adding an MCM
6810 RAM.

as the 74LS138 already on the board). Its
primary function is to gate the Enable clock
with the address 2000-3FFF signal from the
main 74LS1 38 decoder, so that the two 21 1 4
RAMs get a low CS signal only when
the E signal is high and the 2000-3FFF
select signal is low. This is absolutely
necessary to make sure that the RAM grabs
data off the data bus at the right time when
storing. Although this could just as easily

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tS Reader Service index — page 241

Microcomputing, October 1980 63

ADDRESS

BUS

ADDRESS
BUS

Fig. 5. IK RAM addition to the basic computer.

be done with a 74LS00 gate at slightly less
cost, the 74LS138 does a better job since it
also decodes the addresses better — it re-
quires that address bits A12 through A10
also be 0, so that the 2114 RAM only
responds to the 1 K address range from 2000
to 3FFF.

Though we can really make do without
this, it simplifies things if we ever decide to
add another pair of 2114s, since the eight
outputs of SEL2 divide up the 8K address
range from 2000 through 3FFF into eight 1 K
ranges.

We could add another IK of memory by
wiring up still another pair of 2114s in the
same way, except that the CS pin on
this pair would go to pin 14 of SEL2. If it
weren’t for loading the 6802 address and
data buses (and lack of room on the board),
we could thus add a total of 8K memory. In
practice, though, we would find that having
much more than IK of memory would over-
load the buses and start causing other
problems unless we buffered them. Since
this would turn the computer into some-
thing other than what we started with, let’s
not consider that further.

Table 3 is a wiring list that shows all the
wiring needed to add this IK memory ex-
pansion to the computer. As before, con-
nection points marked with a star are points
in the computer where the required signal
can be obtained.

A Few Extra Bits

If you really don’t need a full PIA or ACIA
(or have already added one and find you still
need an extra bit or two of input or output),
then all you need is a flip-flop or three-state
buffer. The idea is to use readily available,

inexpensive ICs (Radio Shack has them),
but take advantage of all the extra unused
74LS138 outputs.

Fig. 6 shows how the 74LS367 hex three-
state buffer can be added to provide six in-
put bits. The six inputs come in from the
left, while the six outputs on the right go to
six bits of the data bus.

The 74LS367 has six three-state buffers
divided into two groups — the top two are
turned on when the signal called Select 2
goes low, while the bottom four go on when
Select 1 goes low.

If we tie these select signals to the un-
used outputs of the 74LS138 address de-
coders, we can select either group of buf-
fers whenever the specified address is used

in a program. (Normally, the two select
signals would be connected together to the
same 74LS1 38 output, but they could go to
two different pins.)

For instance, suppose that both select
pins are connected to pin 12 of the main
74LS138 address decoder (shown in Fig. 9
of the June installment). This pin goes low
whenever any address in the range of
6000-7FFF is encountered in a program.

Whenever the computer program does
any read from any of these addresses, this
signal turns on the 74LS367 input buffers,
and the 6802 does a read from these six in-
put lines. Hence, this makes a simple six-bit
input port.

Since the R/W signal isn’t used any-
where in this circuit, this input port will be
selected regardless of whether we read
from, or write out to, one of the addresses in
the 6000-7FFF range. If we are writing to
such an address, then the 6802 will be put-
ting data on the data bus at the same time
as the 74LS367 does so, and this will result
in garbage on the bus (as well as undesir-
able loading on the bus as two drives try to
force it in different directions). Thus, if we
use a simple port such as this one, we must
make sure that our program only reads from
it, never writes to it.

Fig. 7a shows the correct way to wire a
one-bit output port. One of the data bits
from the data bus goes to the data input of a
type D flip-flop such as a 74LS74, and a se-
lect signal from an address decoder (the
74 LSI 38) goes to the clock. At the end of the
select pulse — the rising edge shown in the
diagram — the data from the data bit is
clocked into the flip-flop.

Though this is the theoretically correct
way to wire an output bit, it has two prob-
lems. First, the D input of the flip-flop adds
an extra load to the data bus, which may

50

RAMI -18

RAM2-18

SEL2-16

A0

*6802-9

RAM1-5

RAM2-5

A1

*6802-10

RAhl-6

RAM2-6

A10

*6802-19

SEL2-1

All

*6802-20

SEL2-2

A12

*6802-22

SEL2-3

A2

*6802-11

RAhl-7

RAM2-7

A3

*6802-12

RAM1-4

RAM2-4

A 4

*6802-13

RAM1-3

RAM 2 -3

A5

*6802-14

RAMI— 2

RAM2-2

A6

*6802-15

RAM1-1

RAM2-1

A 7

*6802-16

RAMI— 17

RAM2-17

A8

*6802-17

RAM1-16

RAM2-16

A9

*6802-18

RAMi-15

RAM2-15

ADDR2000 7

*74LS138-

14 SEL2-

-5

DO

*6802-33

RAM1-14

D1

*6802-32

RAM 1-13

D2

*6802-31

RAMI —12

D3

*6802-30

RAM1-11

D4

*6802-29

RAM2-14

D5

*6802-28

RAM2-13

D6

*6802-27

RAM2-12

D 7

*6802-26

RAM2-11

ENABLE

*6802-37

SEL2-6

GROUND

RAM1-9

RAM2-9

SEL2-4 SEL2-8

R/W 7

*6802-34

RAMI— 10

RAM2-10

RAMSEL 7

RAM 1-8

RAM2-8

SEL2-1?

Table 3. Wiring list for adding IK of RAM with two 2114s.

64 Microcomputing, October 1980

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v* Reader Service index— page 241

Microcomputing, October 1980 65

SELECT 2

FROM

INPUTS

+ 5V

Fig. 6. Simple input port using a 74LS367.

cause problems If the data bus is already
heavily loaded.

Second, since the data bit should be en-
tered into the flip-flop at the end of the En-
able signal, this signal should in some way
be part of the select signal going to the
clock input. Thus, the outputs of the SEL2
decoder 74LS138 1C shown in Fig. 5 would
be suitable, but the outputs of the main
74LS138 would not.

If we don’t use the data bus, then the tim-
ing is not as critical. Fig. 7b shows an alter-
native idea. Here, the select signal from the
74LS138 goes to the clock input of a JK flip-
flop such as the 74LS73, while the J and K
inputs both go straight to +5 volts. With
this connection, the flip-flop will toggle ev-
ery time it gets a clock pulse. Hence, we can
flip the flip-flop simply by selecting the cor-
rect address (so the 74LS138 outputs a
pulse).

The trouble with this circuit is that we can
never be quite sure whether the flip-flop is
on or off at any particular time, since the
computer has no way of knowing whether it
started out set or reset when the power first
came on. In some cases this doesn’t matter
-in generating music, for instance.

But if it does, then we could disconnect
the CLR pin from +5 volts (which was dis-
abling it) and connect it instead to the reset
pin of the 6802. Since this pin is always low
when the system is first turned on, this will
guarantee that the flip-flop will always be
reset when we first power up the system.

Fig. 7c is another possibility. Here we dis-
able the D input and clock (or the JK and
clock inputs of a JK flip-flop) by connecting
them to +5 volts. Instead, we take two dif-
ferent select outputs from the 74LS138 and

66 Microcomputing , October 1980

connect one to the PS (preset) input, and
the other to the CLR (clear) input of the flip-
flop. Now we can set or reset the flip-flop
explicitly.

For example, suppose the PS input goes
to the 6000-7FFF output of the address de-
coder (pin 12), while the CLR input goes to
the 4000-5FFF output (pin 13). Any time we
access any address in the 6000 range, the
flip-flop gets a low PS pulse and sets; if you
access any address in the 4000 range, it will
reset.

Since we only have a few unused outputs
on the 74LS138, we obviously cannot con-
nect too many such flip-flops, but with four
decoder outputs we could trigger three flip-
flops simply by connecting all three resets
to the same output and connecting the
three sets to three outputs. Now we don’t
have completely independent control over
the flip-flops, since they will all reset togeth-
er. But this may still be quite useful.

From Hardware to Software

Having seen how to build, test and even
expand our control computer, it’s time to
examine how to program it. Although the
computer can run programs written in Tiny
BASIC when properly expanded, let’s keep
in mind its primary purpose — to be a dedi-
cated control computer. That requires that
we program it in machine or assembly lan-
guage.

So let’s discuss machine- and assembly-
language programming. Rather than start
at the very beginning, we will assume that
all our readers have some familiarity with
programming in BASIC.

Since 6802 machine language is identical
with that of the 6800, this discussion ap-
plies to both processors.

6802 Internal Structure

When programming in BASIC, we tend to
think in terms of the job to be done, rather
than the way in which it is being done. Ma-
chine- and assembly-language program-
ming is different — you must constantly
think of the hardware that is doing the pro-
gram. Thus, you can write a BASIC program
without even knowing what computer it will
be used on; but to write programs in ma-
chine or assembly language, you must
know what is inside the computer and -to
some extent — how it works. This makes
programming tougher, but also more fun
and more challenging.

Fig. 8 shows a simplified view of what is
inside the 6802 (or 6800) processor. (A few
extra registers, as well as the 128-byte RAM,
are not shown, simply because they do not
concern us at this point.)

Within the 6802, the hardware consists
primarily of a set of various registers, plus
an eight-bit transfer bus that interconnects
them and allows data or addresses to go

back and forth within the processor. A reg-
ister is essentially a group of storage ele-
ments— flip-flops or dynamic memory cells
-that holds a binary number. While a pro-
gram is running, numbers are constantly
being moved back and forth between these
registers.

Some of these transfers are managed by
the 6802’s internal control circuitry and are
completely out of our control; other trans-
fers are directly controlled by the program
instructions we write.

Some of the registers hold eight bits,
some 16 bits. One (the condition code regis-
ter at the top) only holds six. In any case, all
of these are interconnected by an eight-bit
transfer bus, so that each half of a 16-bit
register is connected to the bus separately.
When a 16-bit number is transferred from
one place to another, it is moved in two
eight-bit pieces. This will help to explain
why some instructions are faster than oth-
ers.

Two of these registers are called accu-
mulators; they are the A accumulator and
the B accumulator. An accumulator is a
type of register that can not only hold a
number, but can also do some additional
operations on it, such as addition or sub-
traction. Both 6802 accumulators hold
eight-bit numbers. Virtually all arithmetic
operations in a 6802 system are done in one
of the accumulators.

Accumulators are generally the work-
horses of a computer. There are instruc-
tions for loading a number from memory in-
to an accumulator, for adding or subtract-
ing numbers in an accumulator, or for stor-
ing a number from an accumulator back in-
to memory. In addition, numbers in an accu-

♦5V

Fig. 7. Three simple output ports.

mulator can be tested in various ways,
moved from one accumulator to another or
shifted left or right.

The six-bit register is the condition-code
register. Though it is called a register for
convenience, it really is composed of sever-
al different parts, each of which holds just
one bit. These bits are used to indicate
whether the result of a previous operation
had some specific trait, such as being zero,
nonzero or negative. One of these bits is
also used to control the interrupt system.
(Although this register only has six bits,
when we transfer its contents into an eight-
bit register or into memory, we pick up an
extra two bits along the way. These some-
times fool us into thinking this register real-
ly has eight bits when it does not.)

Another useful register is the index regis-
ter. Though the index register can be used
for a variety of purposes, its most common
use is to hold and manipulate addresses;
thus it is a 16-bit register so that it can hold
a full 16-bit address.

The index register can be loaded from
memory; its contents can be incremented
or decremented (increased or decreased by
1) or stored back into memory. In addition,
the contents of the index register can be
used as a pointer to point to a specific loca-
tion in memory which will be accessed at
some point.

Another 16-bit register is called the stack
pointer. This register points to the next
empty location in the stack; the stack, in
turn, is a memory area set aside for tempo-
rary storage of data and addresses. A com-
mon use for the stack is to hold the return
address from a subroutine — in terms of BA-
SIC, this means that when a go-to-subrou-
tine instruction (such as GOSUB) is exe-
cuted, the computer places into the stack
the address of the instruction it should
return to when the subroutine is finished.
The stack pointer register is simply a
pointer used to indicate which part of the
stack has been filled up and which part is
still empty. As numbers and addresses are
put into or taken from the stack, the pointer
keeps changing, so that it always points to
the next empty location in the stack.

The last 16-bit register of concern to us is
the program counter. Actually, the program-
mer doesn’t have much control over the pro-
gram counter, since there are no instruc-
tions that specifically let you manipulate
that register. But the program counter is im-
portant since it keeps tab on the next in-
struction to be performed in our program. It
is affected by transfer instructions (which
are similar to BASIC’s GOTO, GOSUB or RE-
TURN).

Though a few more registers are inside
the 6800 or 6802, these are used internally
and are not normally used by the program-
mer.

Fig . 8. The inside of the 6802.

If you are familiar with other processors,
you may note that the 6802 registers are dif-
ferent from those you are familiar with. The
register structure of a processor — and the
instructions it has to use them — distin-
guishes one microprocessor from another.
Some processors, such as the 8080 or Z-80,
have many different registers; others, such
as the T MS-9000 or the SC/MP, have few.

Actually, the number of registers does
not really determine whether a processor is
powerful or not, since those processors
that have few registers tend to have instruc-
tions that allow them to do operations that
are optimized to work without them.

Though various articles have compared
different microprocessor structures (see,
for example, the excellent articles by Hal T.
Gordon entitled “Instruction Sets Examined
and Compared” in the March and April 1980
issues of Microcomputing), different pro-
grammers will prefer different processors.
Many programmers like the 6800 and 6802
because it is simple yet powerful; the fact
that its architecture is more traditional
rather than unusual (such as the Tl TMS or
the Signetics 2650) may also have a lot to do
with that.

Computer Languages

Computer programs must be written in a
special way so that the computer will be
able to understand them. This generally re-
quires that we use a certain vocabulary and
a set of grammar rules, much like a human
language. Thus we get the term “computer

language” to describe the way a program is
written.

There are essentially three types of com-
puter languages:

•Machine language is the only language
that the computer can really understand.
Since the computer works with binary dig-
its— ones and zeros — the machine-lan-
guage program is written in these as well.
When a machine-language program is en-
tered into the computer, it can be immedi-
ately performed.

Note that machine language is directly
tied into the hardware of the processor.
Thus, different processors will have differ-
ent machine languages, and a program writ-
ten for one will not run on another (unless
you intentionally copy the language of the
other).

•Assembly language is one step above ma-
chine language. In many ways, it is similar
to machine language in that generally one
instruction in the assembly-language pro-
gram is equivalent to one instruction in the
machine-language program. The difference
is that that instruction consists of numbers
in machine language, whereas it may con-
sist of simple letter codes in assembly
language.

Since assembly language cannot be di-
rectly understood by the computer, it must
first be translated into machine language.
But since the two languages are so similar,
that translation is fairly simple. For short
programs you can do it yourself; for longer
programs this translation is done by still an-

Microcomputing, October 1980 67

other computer program called an assem-
bler.

Since assembly language is so close to
machine language that it is translated on a
more-or-less one-to-one basis (one assem-
bly-language instruction becomes one ma-
chine-language instruction), different ma-
chine languages must result in different as-
sembly languages. An assembly-language
program written for one processor will also
not run on another.

•Higher-level languages, also sometimes
called problem-oriented languages, are at
the top of the list. These languages are
completely different from machine or as-
sembly language and generally require
quite extensive translation into machine
language before they can be executed on
the computer. This translation could be
done manually, but even for short programs
this is not practical; hence, translation is
usually done by a translator program called
a compiler or an interpreter.

Higher-level languages are aimed at a
particular application, rather than a particu-
lar computer. Since extensive translation is
required anyway, there is no need to tailor
the language to fit a machine. A language
such as BASIC is similar whether it runs on
an IBM 370 or a TRS-80. Obviously, though,
the translator for the two computers will be

different, and the resulting machine lan-
guage will also be much different.

The higher-level languages are oriented
toward specific kinds of problems. Lan-
guages such as BASIC, FORTRAN, ALGOL
or MAD are at their best with numeric prob-
lems from math or engineering; COBOL or
RPG might best be suited for business ap-
plications; while languages such as LISP,
SNOBOL or LOLITA might be good for
strings.

(There have been hundreds of higher-lev-
el languages in the few short decades of
computers, including some with interesting
names such as JOVIAL, MADCAP, ADAM
and BASEBALL. If you are interested in a
readable history of the subject, I strongly
recommend Programming Languages: His-
tory and Fundamentals by Jean E. Sammet,
published by Prentice-Hall, Inc., in 1969 and
readily available in larger libraries.)

There are many exceptions. Some smart
assemblers allow a single assembly-lan-
guage instruction to translate into many
machine-language steps. And in some com-
puters, the translator for a higher-level lan-
guage is built-in so that it almost looks as
though this higher-level language is the on-
ly language the machine can understand.
(That is certainly how a TRS-80 must appear
to the beginner!)

In a higher-level language, we are con-
cerned with the job to be done, and not with
the mechanics of how it is to be achieved.
For example, to add two numbers in BASIC,
we simply say

C = A + B

In machine or assembly language, we must
be concerned with small details, such as
where in memory A, B and C are to be found
and what part of the processor will be used
to perform the addition.

Remembering that memory locations are
referred to by their addresses, we might
have A in location 100, B in location 101 and
C in location 102. Then the C = A + B pro-
gram would have to be broken down into
smaller steps such as:

1. Take the number in location 100 and
bring it into accumulator A.

2. Add the number in memory location
101 to whatever is already in accumulator A.

3. Store the number from accumulator A
into memory location 102.

If the three numbers are larger than what
can be stored in just a single eight-bit mem-
ory location, then they might be split up
among several consecutive locations, and
the machine- or assembly-language pro-
gram to perform a simple C = A + B equa-
tion might consist of dozens or even hun-
dreds of steps. ■

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03 = ‘ENTER PURCHASES

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22 = PRINT CASHFLOW FORECAST..

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24 = EXIT SYSTEM

DATABASE MANAGEMENT INCLUDES

*** FILE CREATE/DELETE/SEARCH. ** # RECORD CREATE/DELETE/SEARCH/4 OPTION PRINT. *** RECORD SORT ANY FIELD ALPHA OR NUMERIC. *** INDEX
SEARCH OR GENERAL SCAN/PRINT IN ANY FIELD (EG TOWN OR NAME). * * * 4 ARITHMETIC FUNCTIONS TO USE AS CALCULATOR ON LAST 4 FIELDS. * * * AUTO
CHECK TO PREVENT DOUBLE ENTRY TO FILE MANAGEMENT SYSTEM. DYNAMICALLY ALLOCATING INFORMATION TO MINIMIZE DISK SPACE CONSUMPTION

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G.W. COMPUTERS U.K. ARE THE PRODUCERS OF THIS BEAUTIFUL PACKAGE

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WE EXPORT TO ALL COUNTRIES CALLERS ONLY BY APPOINTMENT CONTACT TONY WINTER ON 01.636.8210
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NOTE!!! All versions, especially 9.00 use broad financial principles and 9.00 is one 16K core program releasing both disk
drives for data storage, as well as being translateable into any foreign language.

68 Microcomputing, October 1980

WE WILL NOT BE UNDERSOLD

16K MEMORY UPGRADE KITS 2 for $85 $45

for TRS-80*, Apple II, (specify): Jumpers $2.50

PRINTERS NEC Spinwriter

| Letter Quality High Speed Printer

Includes TRS-80* interface software, quick
[change print fonts, 55 cps, bidirectional,
high resolution plotting, graphing, propor*
' tional spacing: R.O. $2579

R.O. with Tractor Feed $2679 KSR with Tractor Feed $2995

779 CENTRONICS TRACTOR FEED PRINTER

$969

Same as Radio Shack line printer I

737 CENTRONICS FRICTION & PIN FEED PRINTER $799

9x7 matrix

730 CENTRONICS FRICTION & PIN FEED PRINTER $629

7x7 matrix Same as Radio Shack line printer II
PI CENTRONICS PRINTER $269

Same as Radio Shack quick printer
PAPER TIGER (IP440) $939

Includes 2K buffer and graphics option
TI-810 Faster than Radio Shack line printer III

Parallel and serial w/TRS-80* interface software

with upper and lower case and paper tray $1599
OKIDATA Microline 80 Friction and pin feed $559

Tractor Feed, friction, and pin feed $679

EATON LRC 7000 + 64 columns, plain paper $299

ANADEX DP-9500 $1359 DP-8000 $825

DISK OPERATING SYSTEMS

PATCHPAK #4 by Percom Data

CP/M® for Model I, Zenith $145 • for Model II, Altos

NEWDOS Plus 40 track

NEWDOS 80

$ 8.95

$169.00
$ 99.00
$135.00

ACCESSORIES

HEAD CLEANING DISKETTE: Cleans drive Read/Write head in
30 seconds. Diskettes absorb loose oxide particles, fingerprints,
and pther foreign particles that might hinder the performance of
the drive head. Lasts at least 3 months with daily use. Specify
5V4"or8". $20 ea/$45 for 3

FLOPPY SAVER: Protection for center holes of 5V4" floppy disks.
Only 1 needed per diskette. Kit contains centering post, pressure
tool, tough 7-mil mylar reinforcing rings. Installation tools and
rings for 25 diskettes. $11.95

Re-orders of rings only $ 7.95

EXTERNAL DATA SEPARATOR: Eliminates data separation prob-
lems (crc). Improves reliability. This plug in unit comes fully

assembled and tested. $29.95

RS232 $84.00

DISK-DRIVE EXTENDER CABLES: Fits all mini-disk drives.

$16.95

SIX (6) PRONG ISOLATOR $54.00

AC FILTER/6 PRONG POWER STRIP $39.00

DISK DRIVE CABLES: 2 drive $29.00 4 drive $35.00

DUST COVERS: TRS-80/Apple $ 7.95

PLASTIC DISKETTE HOLDER $ 8.00

RF MODULATOR: Adapts video to TV $35.00

TRS-80 & OTHER MYSTERIES $18.95

CAT MODEM Originate and answer same as $148

Radio Shack Telephone Interface II

LEEDEX MONITOR Video 100 $119

ZENITH Color Monitor $379

SANYO Model VM 4509 Monitor $179

DISKDRIVES $314

40 track, 102K Bytes. Fully assembled and
tested. Ready to plug-in and run the moment
you receive it. Can be intermixed with each
other and Radio Shack drive on same cable.
TRS-80* compatible silver enclosure. 90 day
warranty. One year on power supply. External
card edge included.

FOR TRS-80*

CCI-100 5V«", 40 Track (102K Bytes) for Model I $314

CCI-280 5 Vi ", 80 Track (204K Bytes) for Model I $549

CGI-800 8" Drive for Model II (Vi Meg Bytes) $795

For Zenith Z89

CCI-189 5V«*, 40 Track (102K Bytes) add-on drive $394

Z-87 Dual 5 Vi " add-on drive system $995

DISKETTES — Box of 10(5 Vi")- with plastic library case $24

8" double density for Model II (box of 10) $36

COMPLETE SYSTEMS

ALTOS 64K, DD, SS, 2-Drive, 1MB
TRS-80* Model II-64K
TRS-80* LEVEL II-16K with keypad
TRS-80* Expansion Interface
APPLE 16K

HEWLETT PACKARD HP-85
ZENITH Z89, 48K all-in-one computer

ZENITH Z19

TELEVIDEO 912B $745

ATARI 400 $489

APF M1000 $99

MATTEL INTELLIVISION

$3995
$3499
$689
$249
$989
$2999
$2555
$740
920B $769
ATARI 800 $769
IM-1 $499
$249

SOFTWARE FOR THE TRS-80* SEX

INTELLIGENT TERMINAL SYSTEM ST-80-III BY
LANCE MIKLUS: Enables a TRS-80* to act as a dial-
up terminal on any standard time sharing network.
Provides a TRS-80* with control key, ESC Key,
Repeat Key. Rub Out Key, Break Key, full upper and
lower case support, selectable printer output and
program selectable transmission rates $139

CCA-DATA MANAGEMENT SYSTEM: Automate your
information processing tasks. You can create a file of
customer information; quickly and easily add, delete
or update records; search a file; keep a file in order of
the value in any field; and print records and labels in
any desired sequence or from just a part of a file.
Requires 32K TRS-80 and one drive. $74.95

S & M SYSTEMS

INSEQ-80™: indexed Sequential Access Method
(ISAM) for the TRS-80 Model I. A must for anyone writ-
ing business programs. Eliminate wasted disk space
from direct record processing. Split second access to
any record. Access data records instantly via alpha/
numeric “key” eg. Part NR, zip code or sequentially in
ascending key sequence. Add/modify records in any
order. Access up to three files per program — File'

may be spread over multiple disks. Machine language
processing from your basic program. Utility program
to convert direct files to INSEQ-80 format $49.95

FULLY INTERACTIVE ACCOUNTING PACKAGE:

ISAM (INSEQ-80) based. Includes General Ledger,
Accounts Payable. Accounts Receivable and Payroll.
System runs “stand alone” or “co-ordinated G/L“ at
users option. Based on Osborne accounting method.
Requires 32K, TRS-80, 2 or 3 drives. N/A CA.

General Ledger $99

Accounts Receivable $99

Accounts Payable $99

Payroll $99

Osborne books: Req'd as additional documentation
$20 ea

INVENTORY Requires 32K, TRS-80. 1 drive $125
INSORT-90: Callable form BASIC via USR. Sorts “Ran-
dom” Disk Files. "Disk” to “Disk” sort times — 350
records in 35 secs, 1000 records in 6 minutes, 3500
records in 12 minutes. Machine language processing.
Up to 35 sort keys ascending/descendina. Utility to
build BASIC program. Runs under NEWDOS. $49 95

CP/M BASED SOFTWARE for
Zenith, Altos, Radio Shack, Apple w/Manual

Z-80 SOFTCARD FOR APPLE Your key to future soft-
ware expansion. Get the best of both worlds. Apple’s
6502 and CP/M Z-80. Plug in the card and gel a Z80.
Supports Apple language card and all Apple peripher-
als. Comes with set of three manuals. $339

CCI-TELNET VERSION 5: A communication Package
which enables microcomputer users to communicate
both with Large Mainframes and other microcom-
puters. Extensive commands make it useful in many
applications where communication between com-
puters is necessary. Powerful terminal mode enabling

user to save all data from a session on disk. Com-
pletely CP/M compatible. Multiple communication
protocols supported. Able to transfer files in both
directions without protocol where the other machine
does not support any protocol. Extensive ON-
SCREEN help. Source code provided $149

MICROPRO-WORD-STAR: Menu driven visual word
processing system for use with standard terminals
Text formatting performed on screen. Facilities for text
paginate, page number, justify, center and underscore.
User can print one document while simultaneously
editing a second. Edit facilities include global search
and replace. Read/Write to other text files, block
move, etc. Requires CRT terminal with addressable
cursor positioning. $399

dealer (national/international) inquiries invited Send for FREE Catalogue

The CPU SHOP

TO ORDER CALL TOLL FREE 1-800-343-6522

Massachusetts residents call (617)242*3361

For detailed technical information, call 617/242-3361

Hours: 10AM-6PM (EST)M-F(Sat.till 5)

‘TRS-80 is a Tandy Corporation Trademark ® Digital Research

5 Dexter Row, Dept. K10M
Charlestown, Massachusetts 02129

Massachusetts residents add
5% sales tax

Quantities on some items are limited

v* Reader Service index— page 241

Microcomputing, October 1980 69

The days of complicated, unreliable,
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the ultrabyte memory board

^ 1 Q Q QR I complete kit \

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CONTINENTAL ITS " cTeOIT CANO BUYERS OUT SIDE CONNECTICUT CALL

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From Connecticut Or For Asaiitanco. (203) 354-9375

RESEARCH &

IdevelopmentltdJ

333 Litchfield Road, New Milford. CT 06776 ■
Please send the items checked below: Dept, kio

□ JAWS 16K RAM kit. No. 6416. $199.95.*

□ JAWS 16K RAM fully assembled, tested, burned in,

No. 6416W, $229.95 *

□ JAWS 32K RAM kit. No. 6432, (reg. price $329.95),

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any of the above in 16K blocks up to 64K, No. 16EXP,
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*AII prices plus $2 postage and handling. Connecticut
residents add sales tax.

Total enclosed: $

□ Personal Check □ Money order or Cashiers Check
CJ VISA □ MASTER CHARGE (Bank No )

From Connecticut Or For Asaiitanc

ISMIEIBOK

i Signature

J Print Name

i Address

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* State

7ip

l □ Send me more information

Full Size ASCII Keyboard
Calculator Style Numeric Pad
8K RAM (up to 48K RAM)
Resident 4K Monitor ROM
Interchangeable ROM Pacs

Dual Cassette I/O
Serial and Parallel I/O
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240 x 512 Graphics Resolution
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WE PAY ALL SHIPPING AND HANDLING WITHIN THE U.S.
Connecticut residents please add 7 1/2% sales tax.

MICRO DISCOUNT SERVICE

243 Old Colony Road Eastford, Conn. 06242
(203)974-1214 ^126

12" BLACK & WHITE
LOW COST VIDEO
TERMINAL

Easily interfaced with Radio Shack TRS 80

$159.00 LIST

Will sell 6 feet coaxial cable $5.00
Texas residents add 5% sales tax.

Add $5 for shipping and handling

• Ideal for home, personal and business computer systems:
surveillance monitors • 12" diagonal video monitor • Com-
posite video input • Compatible with many computer
systems • Solid-state circuitry for a stable & sharp pic-
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(Jse Master Charge/Visa or send money order.

Micro Products Unlimited

P.O.Box 1525, Arlington. TX 76010
817/461-8043

Dealer inquiries welcome ^

[ Maxell* or BOysan ]

P A

p T

e felff . f i w J !

....... 77 . G

T 8 SINGLE SIDE N

R DOUBLE DENSITY Box of 10 for $00 E

§ 8” DOUBLE SIDE R

8 DOUBLE DENSITY Box of lOfor $70 A

0 5 V’ MINI Box of 10 for $50 L

, DYSAN" DISKS

B 5V MINI Box of 5 for $25 M

M ( Specify - 8" Soft or Hard Sector/5” Soft or Hard Sector) A

w E

A C.O.D.- $1.00 Additional

N

L 238 EXCHANGE STREET M

J CHICOPEE, MA. 01013 jj

1 413-592-4761 „ U1 C

L established 1960 • closed mondays

ATARI MBHMTI/99’4 PET mJ

MEMOREX

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for your computer or word processor

BUY THE BEST FOR LESS.
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ATARI 800
1 6 K $799*

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Call or write for price list with
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SURPLUS ELECTRONICS

ASCII

ASCII

IBM SELECTRIC
BASED I/O TERMINAL
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• Tape Drives • Cable

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• Cabinets • XFMRS • Heat
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130 Northeastern Blvd.
Nashua, NH 03062 ^122

Phone orders accepted using
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TOLL FREE

603-889-7661 • 1-800-258-1036

70 Microcomputing, October 1980

TRS-80 OTHER NEEDS FILLED FOR LESS

+ + + COMPATIBLE DISK DRIVES WITH POWER SUPPLY AND CASE— 120 DAY WARRANTY + + +

* 40 TRACK (204,800 BYTE/DISK) USE BOTH SIDES, ANTI-CRIMP/POWER PROTECT $329

* 8 IN. DRIVE & P.S./CASE $749 WITH P.S./CASE FOR 3 DRIVES $929

* 80 TRACK (204.8K BYTE) 90 DAY WARRANTY $479

* 4-DRIVE CABLE $28 * * 10 DISKS-5 IN. @ $24-8 IN. <g> $36HARD CASE $3 & 5

••• BASE 2 PRINTER-(60 LINE/MIN, 72,80,96,120 or 132 CHAR. LINE BI-DIRECT DOT MATRIX IMPACT 96
CHAR ASCII, 15 BAUD RATES) $499 2K BUFFER, GRAPHICS, & TRACTOR OPTION AVAIL.* ••

* CENTRONICS 737 $839 + + + + + CABLE @$25

* HARRIS SELECTRIC (WORD PROCESSING-TYPEWRITER & PRINTER) $790

* LOWER CASE FOR CENTRONICS 779/RADIO SHACK LINE PRINTER 1 -EASY INSTALL $99.95

* UPS (UNINTERRUPTIBLE POWER SUPPLY) PREVENT POWER DROP SURGE OR OUT? FROM $195

* CAT MODEM (ORIG/ANS) $144 ++++++++ 16K MEMORY SET (200 NANO) $44

* 16K L2 RADIO SHACK COM PUT t R SYSTEM $649

* APPLE, ATARI, RADIO SHACK MODEL 1/2 HARDWARE/SOFTWARE DISCOUNTED A/R, A/P, G/L, P/R FOR
$360 or $100 EA. (MODEL 1) & $630 OR $165 EA. (MODEL 2). APPLICATIONS INTERACT & ARE COMPLETE &
PROFESSIONAL. WILL RUN ON OTHER COMPUTERS. THIS IS A SPECIAL INTRODUCTORY PRICE.

* ASK FOR FREE FLYER WITH OUR LOW PRICES— DEALER INQUIRIES INVITED MASS. RESIDENTS ADD
5% TAX — F.O.B. TEWKSBURY-FREIGHT EXTRA.

M/C, VISA OR CHECK ACCEPTED. TRS-80 IS A REG. TRADEMARK OF TANDY CORP.

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S25C?

Our 50/80
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lets you connect
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v* Reader Service index — page 241

Microcomputing , October 1980 71

What Is the Utility
Of a Utility?

A profusion of information at a low cost, for one.

Frank J. Derfler , Jr
PO Box 691
Herndon , VA 22070

T he unique data base held by the
typical home computer user
could probably be kept as easily in a
loose-leaf notebook or a stack of 3 x 5
cards. Each user has disks or cassettes
full of programs, but they are many of
the same programs other computer
users have. The amount of data
unique to each individual is limited.

Economically, it makes sense to
centralize the computing capability in
one system, which professionals can
maintain, program and interface. In-
dividuals can subscribe to the cen-
tralized system and share both the
reasonable cost and huge capabilities.
Businesses and corporations have
been doing this with time-sharing ser-
vices for years, but time-shared large
computer systems have not been eco-
nomically available to individuals in
the United States.

Hobby Systems

Computer hobbyists solved the
problem in their own way by estab-
lishing services using microcomputers
and one-at-a-time call-in access.
These are known as Computer Bul-
letin Board Services, Apple Bulletin
Board Services or Forum-80. They
generally provide a public message
capability, often can transfer pro-
grams and sometimes allow running

programs. But they have little or no
capability for storing individual files.

Such services fill a big gap between
home systems and large time-shared
mainframes, but they do not have the
storage or the access to large data
bases unique to big computer utilities.
Individuals in other countries have
been using and enjoying the services a
large computer can provide (see
“Ultimate Consumer Computer, ”
Microcomputing , October 1979, p.
94) . These services are now available
to you via the telephone and your own
computer or home terminal.

The Source

This system is the biggest and the
best to arrive on the scene in a long
time. I will not be too specific about
the features of The Source, because
they change so fast.

An information utility is an entry
into the public data base in an in-
teractive mode. This public data base
includes information you would see in
the newspapers: stock reports, busi-
ness news, real estate, classifieds,
travel, shopping hints and editorials.
All of this information is sorted and
cataloged and ready for recall accord-
ing to your interests.

The Source provides both the UPI
and New York Times news services.
Real estate is a separate category, and
listings, counseling and various run-
ning programs are available. The
classified ads are divided into over 100
different categories, including an ac-

tive bulletin board service similar to
hobby systems. Travel schedules and
reservations, as well as shopping
clubs, wine consultation, education
programs and emergency services, are
available.

The New York Times Consumer
Data Base is a separate service acting
as a current-events encyclopedia with
articles on file from the N.Y. Times
and over 60 other publications. An ex-
tensive mailbox system allows the
transmission of private mail between
individual users. You can review,
read or send messages at any time.
You can also store mail and forward it
to other users. A chat mode is
available for users who arrange to be
on the system at the same time.

The Source operates on a Prime
computer system, medium-sized
hardware with about a megabyte of
main solid-state memory and up to
295 megabytes of disk space. The
Prime computer can also be used by
subscribers to run BASIC and FOR-
TRAN programs. Many standard pro-
grams are available, and the user can
insert any unique programs and
create files for permanent storage.

Connection between your home or
office and The Source in McLean,
Virginia, is done by dialing from your
telephone to data transmission car-
riers, who make use of their own
transmission facilities and facilities
leased from other providers. Several
different carrier systems exist in the
U.S.

72 Microcomputing, October 1980

Carriers connect terminals to com-
puters and computers to computers
and provide the equipment to control
the flow of data. They have some of
their own microwave links and lease
channels on microwave, satellite and
cable systems from other major car-
riers. They reach their customers
through the local dial telephone
systems and a few dedicated lines to
big users.

Their activities are regulated by

period occurs weekdays from 7:00 AM
to 6:00 PM; the low period occurs any
other time. The high- time cost is $15
per hour, and the low-period cost is
$4.25 per hour for most services. Ad-
ditionally, if you store data, you will
pay 3.3 cents per 2048-character
block per day.

The one area in which The Source
could stand improvement is written
documentation and explanation. The
billing scheme is poorly explained.

You can buy a lot of five-dollar hours for all
of the money you might spend on disk drives,
memory and languages.

the FCC, ICC and Congress. They
threaten and are being threatened by
the post office and more traditional
carriers. Despite this, they still
manage to make a buck while pro-
viding more inexpensive service than
the normal long-distance rate.

Telenet and Tymnet are two of
these systems used by The Source.
These services have over 300 entry
points across the country. If you are
near an entry point, you will have no
long-distance toll charges.

When I lived in Montgomery,
Alabama, the two nearest entry
points were Birmingham and Atlan-
ta. Birmingham was closer, but a call
to Atlanta was less expensive because
of the interstate rate structure. I had
to pay for a long-distance call to
Atlanta to use The Source, but the
transmission from Atlanta to Virginia
was paid for out of my user fee. I have
been assured that data transmission
services are going to mushroom in
1980.

A user needs a terminal and
modem. The terminal can be a print-
er or a CRT. If it can save the infor-
mation it receives for playback, re-
transmission or manipulation, it is a
smart terminal. Smart or dumb ter-
minals can be used on computer utili-
ties. The modem connects the termi-
nal to the phone line. The Bell 103/
originate modem at 300 baud is the
standard for the services most of us are
interested in.

This service is not free. Each user
pays a one-time connect charge of
$100. Billing for computer and
transmission service time is divided
into low and high periods. The high

High/low billing times are deter-
mined by recorded home address,
regardless of where you are calling
from.

Some services are never billed at
the low rate. The management pro-
vides a loose-leaf binder with intro-
ductory information, but you have to
spend several hours of serious study
before you understand the services.

I am sympathetic to the difficulty
involved in providing published docu-
mentation on a system evolving so
quickly, but it certainly could be
more descriptive. There are several
different commands used to exit from
specific services. If you don’t use the
correct command, you may not get
out until you hang up the phone.
Don’t hang up without signing
“OFF,” or you may be billed for extra
time.

The documentation is a small hur-
dle easily overcome with experience.

Other minor irritants are (1) the
system sometimes crashes and leaves
you hanging and (2) the system is
often busy, particularly between 6 PM
and 11 PM. I understand that com-
puter expansion is coming, so both of
these situations, common to many
systems, should be improved.

The Source is a tremendous system
with features previously seen only in
dedicated military and educational
networks. Its potential for growth is
enormous, and I do not doubt that
services such as this will be accessed in
some form from the majority of the
homes in the U.S. within seven years

MicroNet

MicroNet is growing so quickly that

it is almost impossible to write about
in a paper-and-print publication. It is
a purer computer utility as contrasted
to the information utility The Source
claims to be. MicroNet, which is
heavily targeting micro users, is a big
time-sharing system used by many
large government agencies and com-
mercial corporations. It features resi-
dent software routines tailored for
Apple and TRS-80 users. It does not
provide the large public data base
available through The Source, but it
is less expensive to join. It has begun
operation of a bulletin board message
service and stock quotation service.

From my experience, I feel that
MicroNet is more reliable than The
Source. If you are mainly interested in
programs and computing, MicroNet
is a bargain. A one-time charge of $9
and an off-hour rate of $5 per hour
allows you to use a tremendously
powerful concentration of 15 main-
frame computers running at least
eight programming languages and a
large menu of utility programs. You
have to ask yourself why you would
struggle to put together an extensive
home computer system when that
much power is available economical-
ly. You can buy a lot of five-dollar
hours for all of the money you might
spend on disk drives, memory and
languages.

Each person must analyze his own
interests and needs and buy accord-
ingly. The spectrum from the 4K
breadboard micro to the cluster of
large mainframes has room for every
system and user. Utilities such as
Source and MicroNet add to the flex-
ibility available to the hobbyist and
small businessman. The expansion of
these utilities and the carriers they use
will bring an ever-increasing amount
of power to the small user. If you
decide to tap The Source, send a
message to me at TCB967.

For information on The Source,
contact Source Telecomputing Corp.
(STC), 1616 Anderson Road,
McLean, VA 22102.

For information on MicroNet, con-
tact Personal Computing Division,
CompuServe, Incorporated, 5000 Ar-
lington Centre Blvd., Columbus, OH
43220. ■

In mid-May, The Source issued a new
Users* Manual and Master Index which
provided much better explanations and
was easier to follow than the old manual.

Microcomputing, October 1980 73

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Darkroom Computerist

Focus in on a “picture perfect” way to use your SWTP.

Marc I. Leavey, M.D.
4006 Winlee Road
Randallstown MD 21133

I believe quite a few “computerphiles” are interested in pho-
tography. Ask a few of your friends, and I bet you uncover
someone with a closet darkroom. Listen to his gripes.

What irritates me is making a test exposure each time I
change enlargement ratios, and setting up title slides for the
numerous slide presentations I give. This article contains
programs that make both these problems vanish.

The Enlarger

Fig. 1 is a diagrammatic representation of a common pho-
tographic enlarger. The negative is placed in a carrier in the
head, and a light source projects the image onto the ea-
sel — kind of like a vertical slide projector. On the easel is a
piece of photographic paper, with a light-sensitive coating
that reacts to the image to produce a print, obtainable after
immersing that paper in a series of chemical baths.

The size of the image is regulated by the height of the head
on the column, and the focal length of the lens. If you as-
sume a constant lens, move the head up and the image gets
larger, down and the image size decreases. However, the
time the paper must be exposed is a function of the amount
of light falling on it. Remember the inverse-square law? The
light on that easel varies as the square of the height. Add to
that the iris, a variable aperture that regulates the amount of
light the head puts out in the first place, and you can see how
things can become complicated.

An Example

You finish making several 4x6 prints of the kids, then de-
cide to shoot for an 8 x 10. So you raise the enlarger head,
cropping a little until it looks “right,” and make a test ex-
posure. From that test you derive the new exposure values,
set them up and make that big print. A knock on the door in-
troduces your spouse, who wants “just a few wallet-sized for
my folks.” You crank the head way down. “Gee, that’s

bright!” Inverse-square law, you know. Maybe one or two test
exposures later, some finished “wallets.”

Why the fuss? Because each of those test prints costs you
time and money . . . maybe not much if you are working in
black and white, but color costs lottabucks! The pros realize
this, and there are gizmos costing hundreds of dollars into
which you program data on an “ideal print,” that is, one you
consider perfect. A probe reads the light on the easel and
directs you or the enlarger to set the correct time and aper-
ture to produce a perfect print.

Another Way

Using that old inverse-square law, there is another way to
do it. If you have data on a “perfect” print, expressed as
height of enlarger head above the easel (Ho) and time of ex-
posure (Tq), the formula:

Fig. 1. Photographic enlarger.

Microcomputing, October 1980 75

0010 REM EXPOSURE TABLE PROGRAM

0020 REM

0030 REM VER 2.0 — II APR 19 79
0040 REM MARC X. LEAVER M* D*

0050 REM

0060 REM SET LINE LENGTH TO FULL WIDTH
007 0 REM AND DIGITS TO FLOATING POINT
0080 LINE 3 OtDIGITS-O
009 0 REM BASE* 0 ALLOWS SUBSCRIPT OF 0
0100 REM AS IN F( 0>

0110 BASE* 0

0120 REM READ IN F-STOPS
0130 FOR I«0 TO 5
0140 READ FCI)

0150 NEXT I

0160 DATA 4# 5. 6*8* 11/ 16*22
0170 HOME

020 0 INPUT "WHAT KIND OF PAPER"* PS
0210 PRINT "FOR A GOOD PRINT* WHAT IS:"
0220 INPUT "ENLARGER HEIGHT"* S

02 3 0 INPUT "UNITS CIN OR CM]"*SS
0240 IF SS«"IN" GOTO 260

0250 IF S$<>"CM" GOTO 230

0260 INPUT "EXPOSURE TIME CSEC)"*T

0270 INPUT "F-STOP"*F

0280 LET K>-1

029 0 FOR 1*0 TO 5

03 0 0 IF F«F(i) THEN K*2tl
0310 NEXT I

0320 IF K> - 1 GOTO 400

0330 PRINT "F-STOPS ON LENS ARE:"

0340 FOR 1*0 TO 5
0350 PRINT FCI)

0360 NEXT I
0370 GOTO 270

0400 PRINT "ENTER TABLE DELIMITERS:"

OftlO INPUT "MINIMUM ENLARGER HEI GHT"* M 1
0420 INPUT "MAXIMUM ENLARGER HEX GHT"* M2
0430 INPUT "INCREMENT OF HEIGHTS"*!

0440 INPUT "PRINT TABLE ON WHICH PORT"*P
0500 PRINT *P

0510 PRINT #P* TABCC30-LENC PS))/ 2); PS
052 0 PRINT #P* TABC < 30-LENCPS) ) / 2) >

0530 FOR J«1 TO LENCPS)

0540 PRINT #P*"-";

0550 NEXT J

0560 PRINT IP

0570 PRINT # P

0580 PRINT #P*SSi

059 0 FOR J-0 TO 5

0600 PRINT #P*TAB<5+5*J);F(J>;

0610 NEXT J
0620 PRINT #P

063 0 FOR D*M 1 TO M2 STEP I
0640 PRINT #P*D;

0650 FOR N«0 TO 5

0660 LET Q*C<<CD/S)»2)*T)/K>*C2tN)

0670 IF Q< 2 GOTO 710

0680 IF Q>99 GOTO 710

0690 PRINT #P* TABC 5* 5*N) * INTC Q+ * 5) J

0700 GOTO 720

0710 PRINT #P* TABC 5* 5*N) *

0720 NEXT N

0730 PRINT *P

0740 NEXT D

0750 SKIP #P* 50- D

0760 INPUT "ANOTHER TABLE"* AS

0770 IF LEFTSCAS* 1)*"Y" GOTO 200

0999 END

Program 1.

calculates the new time of exposure at the new height, if the
same aperture is used.

Aperture is measured in f-stops, a logarithmic expression
of how much light the enlarger is putting out. By reducing the
expression to a common f-stop, you can produce factors that

tHAT KIND OF PAPER ? POLYCONTRAST - NO FILTER
For a GOOD PRINT* WHAT I S«

ENLARGER HEIGHT 7 20
INI TS CIN OR CM] 7 IN
ECPO SURE TIME C SEC) 7 14
F-STOP 7 8

INTER TABLE DELIMITERS:

MINIMUM ENLARGER HEIGHT 7 6
MAXIMUM ENLARGER HEIGHT 7 35
INCREMENT OF HEIGHTS 7 1
FRINT TABLE ON WHICH PORT 7 3

POLY CONTRAST - NO FILTER

IN

4

5.6

8

1 1

16

22

6

--

--

--

3

5

10

7

3

7

14

8

--

--

2

4

9

18

9

--

—

3

6

1 1

23

10

--

--

4

7

14

28

11

—

2

4

8

17

34

12

--

3

5

10

20

40

13

3

6

12

24

47

14

--

3

7

14

27

55

15

--

4

8

16

32

63

16

2

4

9

18

36

72

17

3

5

10

20

40

8 1

18

3

6

1 1

23

45

91

19

3

6

13

25

51

--

20

4

7

14

28

56

--

21

4

8

15

31

62

--

22

4

8

17

34

68

--

23

5

9

19

37

74

--

24

5

10

20

40

81

--

25

5

1 1

22

44

88

--

26

6

12

24

47

95

--

27

6

13

26

51

--

--

28

7

14

27

55

-•

--

29

7

15

29

59

30

8

16

32

63

--

31

8

17

34

67

--

--

32

9

18

36

72

-•

- -

33

10

19

38

76

--

--

34

10

20

40

81

--

--

35

1 1

21

43

86

-•

--

Sample run 1.

allow calculation of correct time at any possible opening.

Integrating this idea into a workable scheme results in
Program 1, written in SWTP BASIC. The program first speci-
fies the type of paper used, as different photographic emul-
sions have different characteristics. Enter the data for a cor-
rect print: enlarger height, time for exposure and f-stop.

After requesting delimiters for a table, the program calcu-
lates the exposure time for the range of specified heights, at
all available f-stops. Sample resultant tables for two dif-
ferent emulsions are shown in Sample runs 1 and 2. Different
types of paper — one black and white, one color — illustrate
the different requirements varied emulsions produce.

Note that times greater than 99 seconds or less than two
seconds are not printed; a dash is inserted instead. This is in
deference to most timers on the market today. Also, while
printed times are rounded off to the nearest whole second,
the actual values are used in calculations to maintain ac-
curacy.

How to Use This Program

Make a good exposure of an average negative. Feed the re-
quested data into the computer, then take the table printed
out to the darkroom. When you change enlargement ratios,
simply measure the enlarger height and read the appropriate
exposure time and f-stop off the table. An accurate, program-

76 Microcomputing, October 1980

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1001

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processor Applications How to

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of applications, including inter-
facing and using machine lan-
guage programming! Details
every phase of logic and
machine decisions. This book is
completely practical . . . while it
contains some theory, its main
focus is on the how-to of using
microprocessor chips. 308 p.,
94 il. Only *14.95 h; *9.95 p.

1183— Troubleshooting Mi-
croprocessors & Digital Logic

A complete guide to modern
microprocessor/microcomputer
troubleshooting and servicing
that shows you how to do it all
... how to understand and trou -
bleshoot digital/logic and mi-
croprocessor circuits, how to dig
into their operating systems,
and how to locate and repair
, 229 il. Only

problems. 308

*12.95 h; *8.

h.

1045 — Programmer’s Guide
To Lisp A step-by-step, easy-
learn guide to understanding
and using LISP the popular lan-
guage of artificial intelligence.
Includes many actual programs
and routines and offers a
simplified method of learning
the best-known artificial intelli-
gence language. Shows how to
write complete LbP programs.
210 p., 117 ii. Only *9.95 h;
*5.95 p.

1062— The A To 2 Book of I
Computer Games Here are 26 ■
exciting and instructive game ?
programs— all tested and ready |
to run, and designed to illus- ■
trate the fine points of computer ■
programming! Each of these ■
sophisticated programs in- J
eludes full documentation on|
how the game works, what the Z
program contains, plus valu- 1
able programming gems. 308 ■
p., 73 il. Only *12.95 h; *8.95 p. ■

1169— The Giant Handbook of Computer Projects. This MAMMOTH 504-page
step-by-step guide to building modern computers and accessories — CPUs,
memories, . I/O hardware, etc.— is a builder’s dream, with projects and
schematics, parts lists, and step-by-step construction instructions to
enable you to build your own systems. 504 p., 217 il. only *1 5.95 h; *9.95 p
1053— Microprocessor Cookbook A chip-by-chip comparison of the most
popular modern microprocessors— including programming, architecture,
addressing, instruction sets, and applications! 266 p.. 124 il. only *10.95
h : *6.95 p

1111— How to Design, Build & Program Your Own Working Computer
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can homebrew your own customized eomputer system complete from power
supply to terminals ... at one-third the cost of an equi *alent commercial
unit! 308 p., 138 il. only *14.95 h; *9.95 p
1088 —Illustrated Dictionary of Microcomputer Terminology Here are clear,
concise, encyclopedic definitions of nearly 4.000 computer terms, “buzz''
words, and jargon currently being used in the exploding new field of
microcomputers, But it's more than just a dictionary— it's a thorough
update on what’s happening in computers and related peripheral systems.
322 p.. 150 il only *12.95 h : *7.95 p
1076— Artificial Intelligence An exciting, thought provoking guide to the
sophisticated techniques used to make machines "think." It carefully
defines artificial intelligence, ©(plains the theory behind advanced compu
ter programming, and shows you how to program your computer to assume
rudiments of humanlike intelligence. 252 p„ 1 18 il only *12.95 h; *7.95 p.
1201 —The Complete Microcomputer Systems Handbook. A complete guide
to microcomputers— how they operate, how to use them, how to program
them, and how to troubleshoot and repair them . . . plus data on applica-
tions and the latest state-of-the-art concepts like magnetic bubble
memories, computers in networks, teaching machines to learn, etc. 322 p.
147 it. only *15.95 h; *9.95

1055 — TMe Basic Cookbook A step- by step guide to writing and using
micro- and mini-computer programs tor everyday household, pastime, and
business applications. Shows how to understand BASIC and write instruc-
tions, enter them into the computer, and interpret results. 140 p.. 49 il. only
*7.95 h, *4.95 p

071 —The Complete Handbook Of Robotics How to design and build ANY
kind of robot . . . including ones with microprocessor “brains "—PLUS how
to interface robots with computers! It's a single sourcebook that contains
all the techniques you’ll need for creating, designing, building, and operat-
ing your own robot. 364 p., 137 il only *12.95 h; *7.95 p
066 — The Illustrated Dictionary Of Electronics Complete, modern defim
tions for well over 20.000 electronics/computer terms! It’s an all-inclusive
dictionary of technical terms that is up-to-date, well-organized and con-
cise. and designed to convey a clear meaning to any term. 882 p , 472 il
only *19.95 h ; *14.95 p

077 — Handbook Of Remote Control And Automation Techniques A com-
plete guide to the application of electronic techniques to the solution of an>
remote control problem. Shows how to interface a minicomputer to contro
household devices 294 p.. 250 il only *12.95 h; *7.95 p
099 — How To Build Your Own Working 16-Bit Microcomputer A step-by
step description of how to construct a working 16-bit microcomputer, using
the 9900 CPU microprocessor. Covers every type of interface required, and
how to use it. 96 p., 73 il. only *3.95 p.

107 — Computerist's Handy Manual Brings together a wealth of data
techniques and useful suggestions. Details all the facts needed to make a
decision about bulk memory, keyboards, displays, hard-copy printers, etc.
64 p.. 39 il only *2.95 n

1 141 — How To Build Your Own Working Robot Pet. An incredible book that
shows you how to construct your own microprocessor-based robot and
program it — with full details on building an ultrasonic sonar distance
measuring navigation system (Soniscan). a hearing method (Excom). a way
of talking (Audigen). and an understandable language and grammar
(Fredian). 238 p , 96 il. only *10.95 h ; *6.95 p
095— Programs in BASIC For Electronic Engineers, Technicians & Ex
perimenters. A broad range of problem-solving programs in computer
BASIC, including BETA Distribution. Chebyshev High-Pass and Low-Pass
Designers. Fourier Analysis. Op-Amp circuits, etc. 140 p.. 26 il. only *8.95 h.
*4.95 p

225— Master Handbook Of Electronic Tables 4 Formulas -3rd Edition A

complete electronics reference library in a single volume— instant info
including charts and diagrams, for everyone in electronics! Contains data
that will help you solve any problem or design any circuit! 322 p.,96 il. only
*14.95 h; *9.95 p

1206— How To Design and Build Audio Amplifiers, including Digital
Circuits— 2nd Edition A complete course in designing and building
audio circuits for ALL electronics applications! Plenty of specialized infor-
mation included. 350 p., 249 il. only *15.95 h; *9.95 p.

1136— Practical Electronics Matb. A comprehensive problem-and-solution
study guide and reference on electronics math and theory (with actual
worked-out examples) that covers ALL the concepts used in electronics,
communications, electricity, etc! 504 p.. 276 il.only *15.95 h; *10.95 p
905— Build-lt Book Of Digital Electronic Timepieces A data-packed guide
to building every timekeeping device you can imagine— rugged shipboard

clocks, second-splitting digital 1C chronometers, decorator digital clocks, a y 0 1 2 — How To Design fc Build Electronic Instrumentation. Shows how to*

nrA/>.x.nn * ■ m Ar a 4rOAiiOnZ>u nfinnH molar A tiHo onH mAAn TIArk JUA rs , • .. . , ■

design special circuits or adapt existing ones to perform a host of functions*

precision timer, a frequency period meter, a tide and moon clock. 294 p.
209 il. only *9.95 h ; *6.95 p

1199— The Master 1C Cookbook Use-it-now" info on every |C family and
function— CMOS and TTL 4000- and 7400-series digital iCs.exotic CMOS,
and linear ICs! It’s a ONE-STOP SOURCE of descriptions, pinouts and
maximum ratings fora// classifications of ICs. 476 p, 707 il only *15.95 h;
*10. 95 p.

960— 1C Function Locator. A versatile new four-way. six-section cross
reference index that lets you classify and identify thousands of different |Cs
made by 40 manufacturers, so you can easily select the right 1C for a
specific job, or quickly determine an iC's function. 224 p.. 28 il. only $8.95
h; *5.95 p

1241— How To Build Youi Own Self-Programming Robot. Complete over
the- shoulder instructions on how to use the 8085 microprocessor to build
Rodney Robot, a robot capable of thinking and learning. It's a straightfor-
ward how-to introduction to the sophisticated subject of robotics and
machine intelligence. 239 p„ 103 il. only *12.95 h; *8.95 p

1085—24 Tested, Ready-To-Run Game Programs In Basic A challenging
collection of fun and game programs in BASIC . . . with detailed program
descriptions, sample printouts, and complete flowcharts, with adaptations
for the TRS-80 and PET* home computers! 24 different mind-testing
games. 266 p., 32 il. only *9.95 h; *6.95 p
is— Modern Digital Communications. A comprehensive guide to using
understanding, and troubleshooting modern digital communications sys-
tems . . . all the theory, all the terminology, all the troubleshooting and
testing data, all the facts about the latest hardware and techniques from
the elementary setup to multiplexers! 308 p , 122 il. only *10.95 h; *6.95 p.

780 — 111 Digital & Linear 1C Projects. A practical sourcebook of circuits —
digital and linear— using off-the-shelf components. Complete specs and
' |C(j —

1000 — 57 Practical Programs And Games In Basic. 57 of the hardest*

working, most enjoyable BASIC programs you've ever seen . . . everything*
from space war games to blackjack, from craps to I Ching. from arithmetic*
progression to statistical permutations to one-arm bandits! 210 p.. 64 il.*

only *10.95 h : *7.95 p.

785— Microprocessor/Microprogramming Handbook. An authoritative*

practical guide to the construction, operation, programming and applies *
tions of microprocessors. Covers every aspect— inside and out, and illus-*
trates microprogramming techniques to build up program loops, sub*
routines, and handle interrupts from other peripheral devices. 294 p., 176 il*

only *9.95 h ; *6.95 p. ■

from simple amplification to sophisticated sensing. 420 p., 210 il only*

*14.95 h ; *9.95 p. ■

1 101 —How To Design & Build Your Own Custom TV Games. The COMPLETE*

book— a GIANT 546-page volume— on designing, building, programming.*
and modifiying all kinds of TV games! It’s a thorough course in game*
circuitry, with detailed how-to-build-it instructions and complete game*

schematics. 546 p.. 244 il. only *14.95 h ; *10.95 p.

984 — CMOS Databook. Everything you need about CMOS— theory, circuits,*
practical applications! A 100% practical course in CMOS devices— covers*
everything from CMOS logic operations to basic analog circuits! Ignores the*
usual math treatment in favor of the day-to-day into used in actual design*
work. 280 p.. 273 il. only *9.95 h; *6.95 p. ■

1142—84 Practical 1C Projects You Can Build. Contains an incredible*
variety of circuits you can build from low-cost, readily available integrated*
circuits— from simple voltage regulators to complete radios, hi-fi tone*
controls, pulse generators, power supplies, electronic rev counter, burglar*
alarms, calculator, ice warming indicator, motor speed controllers. 140 p *
113 il. only *8.95 h; *5.95 p

1050— The Most Popular Subroutines In BASIC. A programmer’s manual to*
the most useful and versatile BASIC subroutines and how to use them on*
any floating point BASIC integrator or computer to avoid tedium, economize*
on computer time, and make your programs run faster. Includes sample*
runs and fail-safe programs. 182 p., 349 il. only *9.95 h; *5.95 p. ■
1 184— The Master Guide To Electronic Circuits. 616 pages and 38 Chapters*
of working models of circuit actions in diagram form, plus a look inside*
components, let you track electron currents and see what’s actually happen-*
ing inside electronic circuits! It’s 5-complete-books-in-l. 616 p.. 302 il*
only *19.95 h; *14.95 p ■

10-DAY FREE TRIAL— NO RISK COUPON

clear layout drawings are provided for every 1C (including phase-locked loop|

IC's) featured, and detailed applications info including all the values|

needed to make it work. 210 p„ 275 il. only *8.95 h; *5.95 p. ■ mm

752 — Computer Programming Handbook. A complete guide to computer* TAB BOOKS IflC., Blue Ridge Summit, Pa. 17214

programmmg and data processing with scores of worked out examples. An ■ p )ease send me the books indicated belOW. [specify ■
extremely comprehensive, informative, and interesting work on digital* .... . . , . . K

edition desired (p) paper or (h) hard]:

ig work (

computer programming, and data processing in general. 518 p.. 114 i!. only |
*12.95 h ; *9.95 p

1015— A Beginner's Guide to Computers & Microprocessors A down-to-M

earth introduction to understanding, assembling, building, programming.*
troubleshooting.and operating your own practical small computer system. H
Theory, programming techniques, hardware, circuitry, applications— every*

□ I enclose $_

Send postpaid

aspect of the subject. 308 p.. 207 il only *9.95 h; *6.95 p.
841— Build Your Own Working Robot Complete instructions

-plans."

schematics, logic circuits, and wiring diagrams— for building Buster, the*
most unique pet in the world! Not for novices, Buster is a sophisticated*
experiment in cybernetics. A learning experience unparalleled in electronic*
construction. 238 p.. 117 il. only *8.95 h; *5.95 p.

1070— Digital Interfacing With An Analog World. A GIANT 406-page hand- 1
book that shows you how to design circuits to interface microprocessors,?
computers, telephones, and other digital devices with the analog world I
that shows you how to really put your microcomputer to work. 406 p., 277 il ?
only *12.95 h; *9. 95 p.

995— Beginner's Guide To Microprocessors. Everything you need to know tc«|
get started with microprocessors and personal computers, from the very*

Book #

basics to their internal architecture, from programming to interfacing with
the outside world . . . including how to select your own computer system. 182 1

p.. 106 il. only *8.95 h; *5.95 p

874— Master Handbook Of Digital Logic Applications. A powerhouse of*
applications and design info on the latest digital devices and logic systems ■
that covers more than common TTL. CMOS, noise-immune high-threshold*
logic (HTL). and emitter-coupled logic (ECL), too. 392 p., 308 il. only *12.95 ■
h; *8.95 p.

(We pay freight)

□ Invoice me on 10-day trial (plus shipping)

□ Charge my VISA or Master Charge account (plus shipping) mt
Minimum order *10.00.

Book # Book ff Book # |

I

I

I
I
I

1

State Zip |

I
I

Name

Company.
Address _

. Phone.

City

□ VISA □ Master Charge

Card No. □□□□□□□□□□□□□□a

Expiration Date Signature.

Pa. add 6% Sales tax. All orders outside USA
must add 15% shipping and be prepaid. MC-1080

v* Reader Service index — page 241

^25

Microcomputing, October 1980 77

WE
DELIVER!

Osborne Business
Software

\W\ \

> v >
<y b

Before you buy the programs that your company is going to
depend on for its accounting, ask the following questions:

Do I get the source
code?

Is it well documented?
Is it fully supported?

(Don’t settle for less.

You cannot make the
smallest change without it.)
(The Osborne documen-
tation is the best.)

(If not, why not? What are
they afraid of?)

The Osborne system is the industry standard accounting
package, with literally thousands of users. We offer an en-
hanced version of that package that will run on most systems
without recompiling.

CRT INDEPENDENCE. The original programs were
designed to run on a Hazeltine terminal. To use a different
CRT, you had to modify and test two modules — and recom-
pile every program! With the Vandata package, you simply
pick your CRT from a menu and run.

FILE/DRIVE MAP. The original package had all data files
on the same drive as the programs. Ours allows you to
dynamically specify the drive assigned to each file. In fact, you
can change the drive assignments whenever you wish, to ac-
comodate expanded file sizes or new hardware — all without
recompiling!

INTEGRATION. The original AR and AP systems had to
be changed and recompiled to feed journal entries to GL. Our
installation program eliminates this hassle. It simply asks you if
you want the systems integrated, and what your special ac-
count numbers are.

SPEED. The original programs used a binary search to ac-
cess the GL account file. We use an enhanced technique that
greatly cuts down on disk accesses, thus speeding up account
lookups significantly in the GL, AR and AP systems.

BUGS. We have corrected a number of bugs in the original
programs. If you find a bug in our programs, we’ll fix it — and
send you a $20 reward! Our users are sent bug fixes in source
form.

MORE! We have made many minor enhancements, and
fixed many minor problems. We are committed to the ongoing
support of our package. Vandata has been an independent
software supplier for over seven years. Quality and support are
our way of doing business.

General Ledger with Cash Journal $95

Accounts Receivable $95

Accounts Payable $95

Payroll with Cost Accounting $95

• All Four Packages (GL, AR, AP, PR) $295

Magic Wand (Super Word Processor!!) $345

Pearl Level III (best prog, tool available) $645

CBASIC-2 $110

TRS-80 MOD II CP/M 2.2 (Pickles & Trout) $185

H89/Z89 CP/M 2.2 (Magnolia inc. h/w mod) $295

Formats: Std. 8". 5’’ NorthStar DD. TRS-80 MOD II tm. H89/Z89, Superbrain DD.
Manuals for GL. AR/AP, and PR are not included in price — add $20 per manual
desired (AR/AP are in one manual). CP/M and CBASIC-2 required to run account-
ing software. Users must sign licensing agreement. Dealer inquiries invited.

To order call: (206) 542-8370

or write: VANDATA ^

17541 Stone Avenue North

Seattle, WA 98133

VISA/MC Welcome — TRS-80 is a registered tm of Radio Shack, Inc.

mable timer, such as the one described in 73 Magazine,
August 1977, pp. 66-71 (“Build a Unique Timer,” WA3AJR), is
an aid to setting repeatable times for this program.

A Finishing Touch

You can use Program 2 to identify slides when you project
them. This program is set up for a scrolling terminal, with H
set to the number of characters per line and V set to the
number of lines. It inputs up to three less than V lines,
centers them and surrounds them with a border character of
your choosing. If you don’t want a border, you can use a non-
printing single character such as CONTROL-G (BELL). A loop
at the end ties things up until you take a picture of the
screen.

I put titles on the screen and shoot them, after thoroughly
cleaning the screen, with ASA 125 Plus-X at f/1.4, 1/8 second.
I use a tripod and darken the room to eliminate reflections
from the screen. The resultant negatives are a black-on-clear
representation of my white-on-black background display and
make snazzy title slides. You can mount them in slide
mounts alone or, with a little creative planning, shoot them
to sandwich with a color slide, producing a superimposed
title. ■

0010 REM SLIDE TITLE MAKER

0020 REM -

0030 REM VER 2.0 - 13 APR 79
0040 REM MARC !• LEAVEY/ M* D-
0050 REM

0060 REM SET LINE LENGTH
007 0 LINE- 0

0080 REM "H" - CHARACTER WIDTH OF SCREEN

009 0 REM ”V” - NUMBER OF LINES ON SCREEN

0100 LET H-32

0110 LET V- 1 6

0120 DIM LS( V) / L( V)

0130 INPUT ’’BORDER CHARACTER”/ BS
0140 IF LENC BS) - 1 GOTO 200

0150 PRINT ’’PLEASE TYPE ONLY ONE CHARACTER”

0160 GOTO 130

0200 LET K-0

0210 FOR N- 1 TO V-3

0220 PRINT ’’LINE #”;N;

0230 INPUT L$( N>

0240 IF LEN(LSCN)) <-H- 5 GOTO 300

0250 PRINT CHRSC 7)1 "LINE TOO LONG ! ”; CHRSC 7)

0260 GOTO 220

0300 IF LSCN>«”#$” THEN N-N-liGOTO 400
0310 LET L(N)«LEN(LS(N) )

0320 IF L(N)>K THEN K-L(N)

0030 NEXT N

0400 LET I-K+4

0410 LET J«<CHM)-I>/2

042 0 PRINT TABCJ);

0430 FOR M*1 TO 1
0440 PRINT B$;

04 5 0 NEXT M

0460 PRINT

0470 FOR M«1 TO N

043 0 PRINT tabcj); bs;

0490 PRINT TAB(C<HM>-LCM)>/2>;LS<M>)

0500 PRINT TABCI+J- l); BS

0510 NEXT M

0520 PRINT TABCJ);

0530 FOR M«1 TO I
0540 PRINT BSi
0550 NEXT M

0560 FOR M» 1 TO V-CN+2)

0570 PRINT
0580 NEXT M

059 0 REM LOOP TO KEEP THINGS BUSY
0600 GOTO 59 0

Program 2.

78 Microcomputing, October 1980

WHAT KIND OF PAPER ? CIBACHROME
FOR A GOOD PRINT# WHAT I S*
BJLARGER HEIGHT ? 21
WITS CIN OR CM3 ? IN
EXPOSURE TIME (SEC) ? 10
F-STOP ? 5

F- STOPS ON LENS ARE*

4

5.6

8

11

16

22

F-STOP ? 4

BJTER TABLE DELIMITERS*

MINIMUM ENLARGER HEIGHT ? 10
MAXIMUM ENLARGER HEIGHT ? 24
INCREMENT OF HEIGHTS ? 1
FfUNT TABLE ON WHICH PORT ? 3

CIBACHROME

IN

4

5* 6

8

1 1

16

22

10

2

5

t

18

36

73

11

3

5

1 1

22

44

88

12

3

7

13

26

52

--

13

4

8

15

31

61

--

14

4

9

18

36

71

--

15

5

10

20

41

82

--

16

6

12

23

46

93

--

17

7

13

26

52

--

..

18

7

15

29

59

--

- -

19

8

16

33

65

• •

--

20

9

13

36

73

--

..

21

10

20

40

80

-•

~ -

22

1 1

22

44

83

--

23

12

24

48

96

..

--

24

13

26 52

Sample

run 2.

What K.. . 1

BEYOND A SCOTT ADAMS

ADVENTURE ?

AUAiiJi

ODYSSEY

* ITEMS NOW HAVE 3-D-abi lity

*

(Insides, Outsides, etc)
MULTI-PLAYER - up to 12
and they can be friend or foe
A* UNRESTRICTED COMMANDS
/V up to full paragraphs!

COMING SOON...
Bug Vour Dealer !

I NTERNATIONAL

Bo* 3435 * Longwood. Fla 32750
(305) 862 6917

BUSINESS PROFESSIONAL GAME
SOFTWARE FOR APPLE AND TRS-80

□ HOME FINANCE PAK I: Complete package $49.95 Apple, TRS-80

□ BUDGET: The heert of s comprehensive home finence system. Allows user to define up to 20 budget

items. Actual expense input can be by keyboard or by automatic reading of CHECKBOOK II files. Costs are
automatically sorted and compared with budget. BUDGET produces both monthly actual/budget/variance
report and a year to date by month summary of actual costs. Color graphics display of expenses. .$24.95

□ CHECKBOOK II: This extensive program keeps complete records of each check/deposit. Unique check

entry system allows user to set up common check purpose and recipient categories. Upon entry you select
from this pre defined menue to minimize keying in a lot of data. Unique names can also be stored for com
pleteness. Rapid access to check files. Check register display scrolls for ease of review. 40 column print-
out. Up to 100 checks per month storage. Files accessible by BUDGET program $19.95

□ SAVINGS: Allows user to keep track of deposits/withdrawals for up to 10 savings accounts. Cpmplete

records shown via screen or 40 column printer $14.95

IH CREDIT CARD: Keep control of your cards with this program. Organizes, stores and displays purchases,

payments and service charges. Screen or 40 column printer display. Up to 10 separate cards $14.95

□ THE UNIVERSAL COMPUTING MACHINE: $39.95 Apple, TRS-80

A user programmable computing system structured around a 20 row x 20 column table. User defines row
and column names and equations forming a unique computing machine. Table elements can be multiplied,
divided, subtracted or added to any other element. User can define repeated functions common to a row or
column greatly simplifying table setup. Hundreds of unique computing machines can be defined, used, stored
and recalled, with or without old data, for later use. Excellent for sales forecasts, engineering design analysis,
budgets, inventory lists, income statements, production planning, project cost estimates-in short for any
planning, analysis or reporting problem that can be solved with a table. Unique cursor commands allow you
to move to any element, change its value and immediately see the effect on other table values. Entire table
can be printed by machine pages (user-defined 3-5 columns) on a 40 column printer. Transform your com-
puter into a UNIVERSAL COMPUTING MACHINE.

□ COLOR CALENDAR: HI-RES color graphics display of your personal calendar. Automatic

multiple entry of repetitive events. Review at a glance important dates, appointments, anniversaries, birth-
days, action dates, etc. over a 5 year period. Graphic calendar marks dates. Printer and screen display a
summary report by month of your full text describing each day's action item or event. Ideal for anyone with
a busy calendar. . (Apple Only) SI 9.95

□ BUSINESS SOFTWARE SERIES: Entire package $199.95 Apple, TRS-80

□ MICROACCOUNTANT: The ideal system for the small cash business. Based on classic T-accounts and
double-entry bookkeeping, this efficient program records and produces reports on account balances, general
ledger journals, revenue and expenses. Screen or 40 column printer reports. Handles up to 500 journal
entries per period, up to 100 accounts. Instructions include a short primer in Financial Accounting. $49.95

□ UNIVERSAL BUSINESS MACHINE: This program is designed to SIMPLIFY and SAVE TIME for the
serious businessman who must periodically Analyze, Plan and Estimate. The program was created using our
Universal Computing Machine and it is programmed to provide the following planning and forecasting tools.

CASH FLOW ANALYSIS PROFORMA BALANCE SHEET SOURCE AND USE OF FUNDS
PROFORMA PROFIT & LOSS SALES FORECASTER JOB COST ESTIMATOR

Price, including documentation and a copy of the base program. Universal Computing Machine $89.95

□ INVOICE: Throw away your pens. Use the ELECTRONIC INVOICE facsimile displayed on your CRT.

The program prompts and you fill in the data. Includes 3 address fields (yours, Bill to and Ship to), Invoice
No., Account No., Order No., Salesman, Terms, Ship Code, FOB Pt. and Date. Up to 10 items per sheet with
these descriptions: Item No., No. of units. Unit Price, Product Code, Product Description, Total Dollar
amount per item and invoice total dollar amount. Generates, at your option, hard copy invoices, shipping
memos, mailing labels, audit copies and disc updates to master A/R files. (48 K) $49.95

□ BUSINESS CHECK REGISTER: Expanded version of the Checkbook II program. Handles up to 500 checks

per month with complete record keeping. (48K) $29.95

□ BUSINESS BUDGET: As described above and companion program to Business Check Reaister. Handles
500 transactions per month, up to 20 cost categories. Accesses BCR files for actual costs. (48K) . . . $29.95

□ ELECTRICAL ENGINEERING SERIES: Both programs $1 59.95 Apple

□ LOGIC SIMULATOR: SAVE TIME AND MONEY. Simulate your digital logic circuits before you build

them. CMOS, TTL, or whatever, if it's digital logic, this program can handle it. The program is an inter-
active, menu driven, full-fledged logic simulator capable of simulating the bit-time by bit-time response of a
logic network to user-specified input patterns. It will handle up to 1000 gates, including NANOS, NORS, IN-
verters, FLIP-FLOPS, SHIFT REGISTERS. COUNTERS and user defined MACROS. Up to 40 user defined,
random, or binary input patterns. Simulation results displayed on CRT or printer. Accepts network des-
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Microcomputing, October 1980 79

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Reader Service index— page 241

Microcomputing, October 1980 81

Start/Exit Routine for CP/M

This assembly-language utility provides links between CP/M and user programs
and permits simplified operation of remote terminals.

Ken Barbier
Borrego Engineering
PO Box 1253

Borrego Springs, CA 92004

I f you program in assembly language
under CP/M, you might find that Start/Exit
routine in this article listing to be a useful
addition to your program library. While
basically written to provide orderly linkages
between CP/M and user programs under
console control, this program provides
other convenient features, all in less than
256 bytes:

1 . It allows you to quickly copy .COM files
from disk to disk, even if you have only a
single disk drive.

2. It provides an exit from CP/M to your
built-in ROM monitor, or to other bootstrap
programs in ROM.

3. It provides a return to CP/M from user
programs or from a ROM monitor.

4. By allowing you to jump between CP/M,
user programs and the ROM monitor under
console control, it permits the operation of
remote terminals without the need for ac-
cess to the computer’s RESET switch or
front panel.

5. It includes a console message output
subroutine that permits you to embed con-
sole messages anywhere within your
assembly-language programs, much like
BASIC PRINT statements.

The Start Program

The source program resides on disk as
library file START.LIB and should be ap-
pended at the beginning of any assembly-
language source program by entering the
ED statement “RSTART.” When thus used
as a library file, line 79 should be replaced
by “ORG 0200H”, so that your user pro-
gram will now start at location 200 instead
of 100, where Start must reside at the begin-
ning of the transient program area.

82 Microcomputing, October 1980

When your assembled user program (in-
cluding Start) that is on the disk as a .COM
file is called by name, CP/M will load your
program and jump to Start, which will then
display the following console message:

B = TAPE BOOTSTRAP
C = CP/M RESTART
M= MONITOR
R = RUN PROGRAM
?:

where ?: is prompting you for one of the four
single-letter directive choices. If you enter
the wrong letter, hit the Rubout key before a
carriage return, and Start will reprompt with

When the correct choice is entered,
followed by a carriage return, Start will
jump to the desired program. If your choice
is R to run your user program, then that pro-
gram can return to Start at address 100
after it has done its thing, allowing you to
make any of the four choices as before.

If you have a good monitor program in
ROM, you might prefer to use it instead of
CP/M’s DDT to debug your new user pro-
gram, so you would enter M instead of R.
When finished with the monitor, it can
reenter Start at location 1 00 to provide a link
back to CP/M.

The Exit Program

If you assemble this program with line 79
as an END statement as shown in the

listing and name the object file EXIT.COM,
then this same routine can be used as an
exit from CP/M to your monitor or a tape
bootstrap program. This is especially
useful if CP/M is a recent addition to your
system, and you have mountains of soft-
ware on cassette tapes.

I hope that when you ran those cables
from the computer room to the bedroom (so
you could play in comfort), you included a
couple of audio cables so you could take
your cassette along with you. Now you can
easily switch between disk programs under
CP/M and cassette programs at your
remote terminal without having to get up to
hit the reset switch.

A Convenient Message Subroutine

Start/Exit includes a console message
subroutine that allows you to place console
messages anywhere within your program
and output them to the console with a
minimum of overhead. For example, you
can output an error message with this sim-
ple sequence:

CALL MSGXP
DB ‘ERROR!’

DB 0DH,0AH,0

Your message can be any length, and the
length parameter does not have to be
passed to MSGXP. Your message text must
terminate in a zero, and the subroutine will
return to your calling program at the State-

Program listing. Start/Exit program in assembly language.

8 :

3E09

=

Cl

EQU

3E09H

j

BIOS 'CONIN'

9)

3 E0C

3

CO

EQU

3E0CH

;

BIOS 'C0N0UT*

1 0 s

3E03

3

WB00T

EQU

3E03H

;

WARM START

1 1 1

2900

3

STAK

EQU

2900H

;

TOP OF USEABLE RAM

12:

C800

3

MONITOR

EQU

0C800H

;

ROM MONITOR

1 3 1

C803

3

TB00T

EQU

0C803H

;

ROM TAPE BOOTSTRAP

14:

15:

16:

17:

18:

0200

3

PROGRAM

EQU

0200H

i

PROGRAM START

0100

ORG

0100H

; TP A START

0100

310029

START

LX I

SP* STAK

J SETUP STACK

19:

0103

FB

El

; ENABLE INTS

20:

0104

CD9101

CALL

MSGXP

; SIGN - ON

21 :

0107

0D0A

DB

0DH* 0AH

; CR* LF

22:

0109

42203D2054

DB

'B = TAPE

BOOTSTRAP'

23 *

01 IB

0D0A

DB

0DH* 0AH

241

01 ID

43203D2043

DB

*C = CP/M

RESTART*

25*

0 1 2D

0D0A

DB

0DH* 0AH

26*

012F

4D203D204D

DB

*M * MONITOR*

27*

013A

0D0A

DB

0DH* 0AH

28*

013C

52203D2052

DB

*R « RUN

PROGRAM’

29*

014B

0D0A00

DB

0DH* 0AH * 0

30*

31 t

014E

CD9101

STAR0

CALL

MSGXP

; PROMPT INPUT

32*

0151

0D0A

DB

0DH*0AH

33*

0153

3F3A20

DB

•7 * *

34*

0156

00

DB

0

35*

36*

0157

CD093E

STAR 1

CALL

Cl

; GET DIRECTIVE

37*

015A

F5

PUSH

PSV

; SAVE I T

38*

015B

4F

MOV

C/ A

; ECHO IT

39*

015C

CD0C3E

CALL

CO

40:

015F

CD093E

STAR2

CALL

Cl

; VAIT FOR CR

41 *

0162

F5

PUSH

PSV

42 t

0163

4F

MOV

C* A

43:

0164

CD0C3E

CALL

CO

44:

0167

FI

POP

PSV

45:

0168

FE0D

CPI

0DH

; IS INPUT CR?

46 :

016A

CA7501

JZ

STAR3

47*

016D

FEFF

CPI

0FFH

; IS IT RUB0UT?

48 :

016F

CA8D01

JZ

STAR4

; YES* RESTART

49 *

0172

C35F01

JMP

STAR2

; GET NEXT CHAR

50:

0175

FI

STAR3

POP

PSV

; RESTORE CHAR

51 *

0176

FE42

CPI

•B*

; PROCESS DIREC

52*

0178

CA03C8

JZ

TB00T

53*

017B

FE43

CPI

*C*

54*

017D

CA033E

JZ

VB00T

55*

0180

FE4D

CPI

•M *

56*

0182

CA00C8

JZ

MONITOR

57*

0185

FE52

CPI

'R*

58*

0187

CA0002

JZ

PROGRAM

59*

018A

C34E01

JMP

STAR0

; ILLEGAL!

60*

0 1 8 D

FI

STAR4

POP

PSV

*' KILL DIREC

61 :

0 1 8 E

C34E01

JMP

STAR0

*• GET NEV ONE

62*

63*

*

64:

* OUTPUT MESSAGE TO CONSOLE

65*

* AND RETURN

THRU INDEX

66*

*

67*

68:

0191

El

MSGXP

POP

H

GET

CALL ADRS + 1

69*

0192

7E

MSGX1

MOV

a* m ;

GET

CHARACTER

70:

0193

FE00

CPI

0

TIL

END OF MESSAGE

71 *

0195

CAA001

JZ

MSGEX

THEN

1 EXIT

72*

0198

4E

MOV

C* m

CHARACTER TO (C)

73*

0199

CD0C3E

CALL

co ;

OUTPUT CHARACTER

74:

0 1 9C

23

I NX

h ;

AHEAD ONE

75:

019D

C39201

JMP

MSGXl ;

CONTINUE TIL DONE

76:

01A0

23

MSGEX

I NX

H

AHEAD TO NEXT

77:

01A1

E9

PCHL

*

INSTRUCTION* AND GO!

78*

79*

01A2

END

ment immediately following the zero.

MSGXP uses the A, C and H, L registers,
so if you need to preserve the contents of
these registers, you will have to surround
your CALL and the message text with ap-
propriate PUSH and POP statements.

There is quite a bit of program space left
between the top of Start and the beginning
of user program space at location 200. You
can use this room for additional jump op-
tions. Both the header message text and
the directive processing in the program
listing are organized to make it easy to add
options.

In any case, it would be a good idea to
leave the start address of all user programs
at location 200, even if some space is
wasted. Then you will always know where
your program begins.

Single Drive Disk Copy

With Start appended to your program, it
is easy to copy that program onto another
CP/M disk even with a single drive system.
When Start prompts with ?: place the
destination disk in the drive and enter C and
a carriage return to reboot CP/M from the
new disk. When CP/M prompts with “A>”
enter “SAVE x X.COM”, where X is your pro-
gram name and x is the appropriate size in
256 byte blocks.

By rebooting CP/M, you enable writing
onto the new disk. Your user program re-
mains undisturbed in memory during the re-
boot, ready to be saved.

The absolute addresses in the EQUate
statements are for a 16K version of CP/M.
The addresses given for the monitor and
tape bootstrap programs are for a specific
hardware system, and you will have to
change them to the proper entry points for
your own ROM programs. ■

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v* Reader Service index — page 241

Microcomputing, October 1980 83

Modifying the Horizon
Double Density DOS

Programming tricks to really personalize your system.

George L Haller
1500 Galleon Drive
Naples , FL 33940

T he Horizon disk operating system for
double density is a wonderful collection
of instructions. But it lacks some of the per-
sonalized features that would make it even
better.

The Modifications

There are three modifications I think can
improve the system.

1. On many occasions, I would like to
have the video display and the printer work
at the same time without modifying the BA-
SIC program. Since the first serial output is
for the video terminal and the second serial
output is available for a peripheral, all I
need is to make them work together in tan-
dem. I then will have the video displaying
the output while the output is also being
printed.

2. I would like the ability to output the
desired number of nulls. Some peripherals
in the serial mode require a certain number
of nulls after CR/LF. This feature was in-
cluded as a command in the older North
Star BASIC, but was eliminated some ver-
sions ago.

3. 1 would like to be able to output spaces
after a CR/LF. This feature is useful when a
line printer prints too close to the left-hand
edge of the paper and does not leave
enough space for binding the pages. It is
especially convenient for listing where you
do not have control of the page format.
The first modification is simple because

of the output code setup. The first serial
output is a subroutine starting at 293EH
with a Return, C9H, at 2948H. This is fol-
lowed by the second serial output at 2949H
with a Return at 2953H. All you need to link
the two outputs is to replace the first Return
with a NOP, and you will be able to watch
the video while the printer is working away.

This is easily done in BASIC by Fill
10568,0. To return to normal operation use
Fill 10568,201.201 is the decimal equivalent
of C9H, which is Return. This is shown in
Listing 1.

The second modification, to add nulls, is
more difficult, since you must key on the
CR/LF to determine when to add the nulls.
Actually, you key on the line-feed character.
Listing 2 shows the necessary changes.

There is adequate space beginning at
29BCH to accommodate your new sub pro-
gram so that at COUT1, 2949H, you will
jump to the patch named COUT3 with
C3,BC,29.

The remainder of the codes in COUT 1 are
not used. The codes shown in Listing 1 are
inserted and used. This particular set in-
serts seven nulls, but this number may be
changed at 29CCH.

The third modification, the insertion of
spaces at the beginning of each line, can be
assembled similarly. Listing 3 shows a com-
bination of both nulls and spaces, with
seven nulls and five spaces.

These programs are versatile, and If
residing in DOS, may be changed by the
BASIC FILL command.

ITHE FOLLOWING IS A PATCH IN USER'S AREA OF N*
I HORIZON DOUBLE DENSITY DOS TO ALLOW THE
IOUTPUT ON TERMINAL I AND TERMINAL 2 IN
? TANDEM AND CONTINUOUSLY. THIS PATCH IS
I IS MERELY CHANGING 2948 FROM C9 TO NOP.

I THIS CAN BE DONE IN BASIC BY FILL 10568,0
I AND RETURNED TO NORMAL BY FILL 10568,201

293E

DB03

COUO

IN

3

1 INPUT FIRST SERIAL PORT STATUS

2940

E60 1

AN I

1

IMASK OUTPUT STATUS BIT

2942

CA3E29

JZ

COUO

«LOOP IF NOT READY TO OUTPUT

2945

78

MOV

A,B

tMOVE CHARACTER TO A

2946

D302

OUT

2

1 OUTPUT THE CHARACTER

2948

C9

RET

1 CHANGE TO NOP TO OUTPUT
I TO BOTH SERIAL PORTS

2949

DB05

COUTI

IN

5

I INPUT SECOND SERIAL PORT STATUS

294B

E601

ANI

1

IMASK INPUT STATUS BIT

294D

CA4929

JZ

COUTI

I LOOP IF NOT READY TO OUTPUT

2950

78

MOV

A, B

IMOVE CHARACTER TO A

2951

D304

OUT

4

IOUTPUT THE CHARACTER

2953

C9

RET

Listing 1. Modification to link two outputs.

84 Microcomputing, October 1980

10 Input "DEVICE NUMBER", Z

20 PRINT #Z, “THIS WILL PRINT ON THE SELECTED

DEVICE”

30 PRINT “THIS WILL PRINT ON THE VIDEO TER-
MINAL”

Table 1.

If only the null change is made as shown
in Listing 2, any number of nulls may be in-
serted in the DOS by FILL 10700, XX, where
XX is the number of desired nulls in
decimal. 10700D = 29CCH.

If the null and space version (Listing 3) is
in use, then FILL 10700, XX will insert XX
nulls and FILL 10714, YY will insert YY
spaces.

Implementation

Bring up your DOS and load it at 4000H by
LF 4000. Then go to the monitor at 0 or
2D00H. The monitor should be loaded
where it will not interfere with the operating
DOS or the loaded DOS. The loaded DOS
uses 4000 H to 4CFFH. The modifications

• THE FOLLOWING IS A PATCH IN USER'S AREA OF N*
•HORIZON DOUBLE DENSITY DOS TO INSERT NULLS AND
•SPACES AFTER A CR/LF. THIS PATCH IS JUMPED TO BY THE
ISMALL PATCH FROM THE BEGINNING OF COUTI AT 2949H.
»01/l 0/80

2949

C3BC29

29BC

78

COUT3

MOV

A V B

IPUT CHAR IN REG A

29BD

FEOA

CPI

OAH

«IS IT A LF?

29BF

CAC529

JZ

LNFD

1 YES

29C2

C3E829

JMP

OUTPT

INO

29C5

CDE829

LNFD

CALL

OUTPT

• OUTPUT THE LF CH*R.

29C8

C5

PUSH

B

ISAVE C

29C9

0600

MVI

B*0

• NULL CHAR. TO B REG.

29CB

0E07

MV I

C,7

INO. OF NULLS TO C REG.

29CD

OD

NULLS

DCR

C

IDECR. C REG.

29CE

FAD729

JM

SPACE

1 IF ALL DONE W/NULLS

29DI

CDE829

CALL

OUTPT

IOUTPUT A NULL

29D4

C3CD29

JMP

NULLS

IDO IT AGAIN

29D7

0620

SPACE

MVI

C, 5

ISPACE CHAR. TO B REG.

29D9

OE05

MVI

C*5

INO. OF SPACES TO C

29DB

OD

SPACE 1

DCR

C

IDECR. C REG.

29DC

FAE529

JM

POPI

1 IF ALL DONE WITH SPACES

29DF

CDE829

CALL

OUTPT

IOUTPUT A SPACE

29E2

C3DB29

JMP

SPACE!

IDO IT AGAIN

29E5

Cl

POPI

POP

B

•RESTORE C

29E6

78

MOV

A, B

IMAKE A-B

29E7

C9

RET

29E8

DB05

OUTPT

IN

5

•FOLLOWING IS A COPY

29EA

E60I

ANI

1

•OF THE COUTI CODE

29EC

CAE829

JZ

OUTPT

29EF

78

MOV

A, B

29FO

D304

OUT

4

29F2

C9

RET

Listing 3 . Modification to insert spaces at the beginning of each line.

may be inserted into the loaded DOS by us-
ing the FM or the DS command from the
monitor. But, while the code will end up in
the 2900s, it should be loaded into the 4800s
instead of the 4900s.

In other words, the first three codes in-
serted would start at 4848H and would be
C3,BC,29, and the next inserted codes
would start at 48BCH and be 78,FE,0A.
When you have made the modifications,
use the monitor command OS to get back to
the operating DOS and then SF DOS 4000,
which will save your new DOS and let you
try it.

One other trick in manipulating the out-
put to the various terminals is to use the
output device capability of North Star
BASIC. You can put a line in the BASIC pro-
gram requesting the input of the output
device number, and then use it as needed in
the program. While this is described in the
manual, the short program in Table 1 may
give one an idea of how it works.

This comes in handy when only part of
the output is to be printed and the re-
mainder goes to the video terminal.*

ITHE FOLLOWING IS A PATCH IN USER'S AREA OF N*
IHORIZON DOUBLE DENSITY DOS TO INSERT NULLS AFTER
I A CR/LF. THIS PATCH I S JUMPED TO BY THE SMALL
IPATCH FROM THE BEGINNING OF COUTI AT 294 9H.
101/10/80

2949

C3BC29

29BC

78

COUT3

MOV

A,B

IPUT CHAR IN REG A

29BD

FEOA

CPI

OAH

IIS IT A LF?

29BF

CAC529

JZ

LNFD

• YES

29C2

C3DA29

JMP

OUTPT

•NO

29C5

CDDA29

LNFD

CALL

OUTPT

• OUTPUT THE LF CHAR.

29C8

C5

PUSH

B

ISAVE C

29C9

0600

MVI

B, 0

INULL CHAR TO B REG.

29CB

OE07

MVI

C* 7

|7 NULLS TO C REG.

29CD

OD

NULLS

DCR

C

• DEC. C REG.

29CE

FAD729

JM

POPI

•IF ALL DONE NITH NULLS

•RESTORE C

29D1

CDDA29

CALL

OUTPT

•OUTPUT A NULL

29D4

C3CD29

JMP

NULLS

IDO IT AGAIN

29D7

Cl

POPI

POP

C

•RESTORE C

29D8

78

MOV

A, B

•MOVE B TO A

29D9

C9

RET

29DA

DB05

OUTPUT

IN

5

• FOLLOWING IS A COPY

29DC

E60I

ANI

1

•OF THE COUTI CODE

29DE

CADA29

JZ

OUTPT

1

29EI

78

MOV

A,B

1

29E2

D304

OUT

4

1

29E4

C9

RET

1

Listing 2. Modification to add nulls.

TRS

80

• F(ast) F(ourier) T(ransform)

• Digital Filter Simulation

• Linear and Exponential Curve Fit

• Disk or Cassette Data & Results Files

• Interactive Graphics

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FFT-80 DISK $30.00

FFT-80 CASSETTE $25.00

Microcomputing, October 1980 85

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86 Microcomputing, October 1980

DR. DALEY’S BEST Mailing List Is Now Better!

DR. DALEY has taken his best selling mailing list and made it even better! This version has
been totally revised to increase the reliability of the files and make it even easier to operate.
Several new features have been added:

• Goof-proof input routine. Eliminates the irritating results of accidentally pressing
some cursor control keys. This is a machine code routine so it is as fast as you are!
BONUS — Auto repeat on all keys!

• Interface to allow output of the entire mailing list or virtually ANY subset to WORD-
PRO III and WORDPRO IV format files so you can use these to generate personal-
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• Routines to merge files and to minimize the number of duplicate entries in a file.

• More machine code routines to speed up processing.

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This system is completely menu driven. It includes 100 pages of user documentation. This
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This program will be available for a short time at the introductory price of $159.95. It is
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is 0 Reader Service index— page 241

Microcomputing, October 1980 87

PET Mini Monitor

This short routine hides in the second cassette buffer
and makes creating and saving machine-language programs a snap.

William H. Perdue
2815 Pulaski Pike
Huntsville, AL 35810

I f you have ever tried any real-time graph-
ics on your PET, you have undoubtedly
found that BASIC is sometimes too slow.
Normally, the answer is to use machine-lan-
guage subroutines that can be linked to
your main BASIC program through the SYS
command.

However, entering the machine code for
the subroutine into the machine is a clumsy
and time-consuming operation, even
though this can be done using BASIC. Ev-
erything must be converted from hexadeci-
mal to decimal and then poked into the
proper memory locations. Another draw-
back occurs when you have to locate and
correct errors, or make changes, in your ma-
chine-language routines. Again, it is possi-
ble to do this using BASIC, but not very effi-
ciently.

Another drawback becomes apparent af-
ter you get your program written, entered in-
to the machine, with everything working
correctly together, and then you try to save
it on tape. The normal SAVE operation will
only save the program that is written in
BASIC, and the machine-language routines
are ignored. The only way around this is to
rewrite the entire program, putting the ma-
chine code into DATA statements and in-
cluding a routine to read and poke the data
into the necessary memory locations. Al-
though this will now allow you to save the
complete program in BASIC, it does use up

a considerable amount of memory.

You can deal with all of these drawbacks
using BASIC, although inconveniently, but
there is a better way. This article describes
a machine-language monitor program that
allows you to read and write memory direct-
ly in hexadecimal form. This eliminates the
need to convert from hexadecimal to deci-
mal for entry, thereby reducing the possibil-
ity of errors. You can write, enter and check
your programs in hex, which simplifies the
task of machine-language programming.
Most important is the ability to save the pro-
gram once you have it written and checked
out.

Machine-language monitor programs are
not new; there is an excellent monitor pro-
gram available for the PET that does all of
the things I have covered and more. How-
ever, the program did not meet my particu-
lar needs. It required about 875 bytes of
user RAM, which I was not willing to give up
just for the convenience of writing machine-
language code.

I needed a short and simple program that
would do the job without using my BASIC
text memory. Since I don’t have a second
cassette unit on my PET, I have 198 bytes of
memory available at the end of page two of
memory. With this in mind, I developed the
PET Mini Monitor.

Program Description

Mini Monitor is a machine-language pro-
gram that resides in the second tape buffer.
Operation of the program is similar to the
KIM operating system. The program allows
the user to open and display all memory ad-
dresses, modify data in RAM-type memory
and save programs on tape from any point
in memory. The program does not affect the
normal BASIC interpreter operating sys-

tem. This allows the user to access one—
either the Mini Monitor or the BASIC inter-
preter operating system— without having
any detrimental effect on the other.

Instructions

First, you must enter the program into
your machine. If you have the PET TIM pro-
gram, you can use it to enter the machine
code from the listing; otherwise, use the
BASIC program in Listing 1. Carefully type
in the program and check the DATA state-
ments to be sure you have made no mis-
takes before you run the program. Once you
have run the BASIC program and have the
machine code in the machine, the normal
READY indication should display on your
screen.

If you have a new PET or have installed
the new ROM set in your machine, do not try
to run Mini Monitor. The zero-page alloca-
tion is different in the new operating sys-
tem, and the program can cause you to lose
your operating system. If you have one of
the old PETs and have the normal READY
indication after loading the machine code,
you can run the program. You must type
SYS(826) and press the return key. This will
link in the machine-language program and
produce the following display:

MM

0400 00 ( )— Blinking cursor

This start display should appear every
time you enter the program. The MM indi-
cates that you are running Mini Monitor and
have successfully entered the program. The
four-digit number is the hexadecimal mem-
ory address, which is followed by a two-
digit number that shows the hexadecimal
contents of the memory cell. The actual
value of the two-digit number will depend on
the contents of memory at the time of dis-

88 Microcomputing, October 1980

0401 00 4C 4C entered into address 0401

0402 00 43A 3A entered into address 0402

0403 00 3 03 entered into address 0403

0404 00 0 00 entered into address 0404

•Note: The actual value displayed in this column will depend on the contents of
memory at the time of the display and may not be the values shown.

Table 1.

0401 4C F6B1: new address entered and RETURN pressed

F6B1 A5 ( )— Blinking cursor new address displayed

F6B1 A5 FI: new address 00F1 (leading zeros assumed)

00F1 01 ()— Blinking cursor

00F1 01 F6033A: new address 033A (four characters preceding the colon)

033A D8 ()— Blinking cursor

033A D8 : return to start

Starting

04 00

05 3A Ending

Address

Hi Lo

Hi Lo Address

SYS(826)

RETURN pressed (enter Mini Monitor program)

MM

0400

XX*

E5:

first address to be inspected (address 00E5)

00E5

XX

3A

enter ending address Lo byte

00E6

XX

05

enter ending address Hi byte

00E7

XX

FI:

next address to be inspected (address 00F1)

00F1

XX

01

enter 01 always (01 =Tape #1)

00F2

XX

F7:

next address to be inspected (address 00F7)

00F7

XX

00

enter starting address Lo byte

00F8

XX

04

enter starting address Hi byte

00F9

XX

20

always enter 20 at this address

00FA

XX

00

always enter 00 at this address

•Note: The XX represents the contents of the address before modification.

Table 3.

MM

0400 00 ( y - Blinking cursor

Table 2.

Address

00E5 enter FF

OOE6 enter 03

00F1 enter 01

00F7 enter 3A

nnCQ nninr (V)

Uvr 0 enxer uo

OOF9 enter 20

00FA enter 00

play. To open and display the next sequen-

Type S and press RETURN

Type MINI MONITOR and press RETURN

tial memory cell, just press the RETURN

key. Your display should now appear as

follows:

Table 4.

MM

When you want to return to the BASIC in-
terpreter operating system, type X and
press the return key. You should then see
the familiar READY display. If not, you must
turn off the power to reset the machine.

MM

0400 00 X exit to BASIC
READY.

( )— Blinking cursor

The Mini Monitor program allows you to
name and save programs from any point in

0401 00 ()- Blinking cursor

To change the data in a memory address,
type the new hexadecimal data and press
the return key. The program will enter the
data in the last open address and then open
and display the next sequential memory ad-
dress. Only the last two numbers typed be-

ing the new address to be opened and dis-
played.

Only the last four characters preceding
the colon will be used to establish the new
address. If there are less than four charac-

memory. However, due to the save routine
utilized, certain addresses must be set to
specific values to assure correct save oper-
ation. Furthermore, you must know the
hexadecimal starting and ending ad-
dresses of the program you want to save.
The Mini Monitor program may be used to

fore the return key will be entered into mem-
ory. If only one number is typed before the
return key, the most significant digit of the
data is automatically assumed to be zero.
Table 1 shows some examples of how to
change data in a memory address.

If you want to check if the correct value
was entered into memory, type t (up arrow)

ters preceding the colon, leading zeros are
automatically assumed for the new ad-
dress. If there are no characters preceding
the colon, the program automatically
returns to the start and displays address
0400. Examples of how to change the ad-
dress being displayed are shown in Table 2.

inspect the specified addresses and modify
the data as needed. These modifications
must be made prior to executing the save.
Table 3 lists the steps necessary to save a
program that has a starting address of 0400
and an ending address of 053A. Using the
Mini Monitor, you would inspect and modify

and press the return key. This will cause the
program to open and display the previous
memory cell. Repeating the operation will
again cause the next previous memory cell
to be displayed. You can continue in this
manner as long as you wish, going back-
ward through memory. With the examples
in Table 1, the display is as follows:

0405 oo t
0404 oo t
0403 03 t
0402 3A t

0401 4C ( )- Blinking cursor

The Mini Monitor program automatically
starts to open and display memory at hexa-
decimal address 0400 and continues se-
quentially after that. To change the address
to be displayed next, type the hexadecimal
address you wish to display, then type : (co-
lon) and press the RETURN key. The new ad-
dress followed by its contents will then be
displayed. Pressing the return key will
cause the next sequential address follow-

10 FOR AD=826 TO 1023
20 READ D$

30 L=ASC(LEFT$(D$,l))

40 R=ASC(RIGHT$(D$,l))

50 IF L>64 THEN L=L-7
60 1=(L-48)*16
70 IF R>64 THEN r=R-7
80 d=L+(R-48)

90 POKE AD,D
100 NEXT AD: END

110 DATA D8, 20, 36,E2,A9,4d,20,A7,03,A0, 00 ,A9, 04,85,50,20
120 DATA D2,C9,A5,5C,20,AD,03,98,20,AD,03,20,A5,03,B1,5B
130 DATA 20,AD,03,20,E6,03,E0,00,F0,2F,B5,1F,C9,5E,D0,0A
140 DATA 88,C0,FF,D0,DA,C6,5C,4C,49,03,C9,3A,D0,0E,CA,8A
150 DATA F0,BE,20,C6,03,A8,20,C3,03,4C,47,03,C9,58,F0,5B
160 DATA O9,53,F0,0D,20,c6,03,91,5B,c8,D0,B3,e6,5C,4c,49
170 DATA 03,20,E6,03,86,EE,A2,00,4C,B1,F6,A9,20,20,D2,FF
180 DATA 4C,D2,FF,48,4A,4A,4A,4A,20,B8,03,68,29,0F,18,C9
190 DATA 0A,90,02,69 S 06,69,30,D0,E7,8A,F0,12,20,D9,03,E0
200 DATA 00 ,F0 ,0B ,85 ,FE ,20 ,D9 >03 ,0A,0A ,0A ,0A ,05 ,FE ,60 ,CA
210 DATA B5, 20,18, 09,41,90, 02,69, 08,29,0F, 60 ,A2,00, 20 ,A5
220 DATA 03,20,CF,FF,C9,0D,F0,F3,E0,10,F0,F5,95,20,E8,D0
230 DATA F0 ,00 ,00 ,00 ,00 ,00

Listing 1. BASIC program.

Microcomputing , October 1980 89

hoc.

Code

Label

Symbolic

033A

D8

START

CLD

033B

20

36

E2

JSR CLSCR

033E

A9

i*D

LDA #’M

03**0

20

AT

03

JSR WRTW

03**3

A0

00

ldy #00

03U5

A9

01*

LDA #01*

031*7

85

5C

INAD

STA ADRH

031*9

20

D2

C9

DISP

JSR CRLF

03l*C

A5

5C

LDA ADRH

03UE

20

AD

03

JSR WRBY

0351

98

TYA

0352

20

AD

03

JSR WRBY

0355

20

A5

03

JSR SPTW

0358

B1

5B

LDA (ADRL) ,Y

035A

20

AD

03

JSR WRBY

035D

20

E6

03

JSR INPUT

0360

E0

00

CKINS

CPX #00

0362

F0

2F

BEQ OPEN

0361*

B5

IF

LDA BUF-1 ,X

0366

C9

5E

CMP #’f

0368

D0

0A

BNE CKCOL

036a

88

DEY

036B

C0

FF

CPY #$FF

036d

D0

DA

BNE DISP

036f

c6

5C

DEC ADRH

0371

hC

h9

03

JMP DISP

037**

C9

3A

CKCOL

CMP #' :

0376

D0

0E

BNE CKX

0378

CA

DEX

0379

8a

TXA

037A

F0

BE

BEQ START

037C

20

c6

03

JSR PKBY

037F

A8

TAY

0380

20

C3

03

JSR CKBY

0383

hC

hi

03

JMP INAD

0386

C9

58

CKX

CMP #'X

0388

F0

5B

BEQ EXIT

038a

C9

53

CMP #’S

038 c

F0

0D

BEQ SAVR

038E

20

c6

03

JSR PKBY

0391

91

5B

STA (ADRL) ,Y

0393

C8

OPEN

INY

0391*

D0

B3

BNE DISP

0396

E6

5C

INC ADRH

0398

1*C

1*9

03

JMP DISP

039B

20

e6

03

SAVR

JSR INPUT

039E

86

EE

SAVIT

STX FNLEN

03A0

A2

00

LDX #00

03A2

i*c

B1

f6

JMP SAVE

03A5

»

Subroutines follow

03A5

A9

20

SPTW

LDA #$20

03A7

20

D2

FF

WRTW

JSR WRT

03AA

he

D2

FF

WRON

JMP WRT

03AD

;

03AD

1*8

WRBY

PHA

03AE

hA

LSR

03AF

hA

LSR

03B0

hA

LSR

03B1

hA

LSR

03B2

20

B8

03

JSR WRASC

03B5

68

PLA

03B6

29

0F

AND #$0F

03B8

18

WRASC

CLC

03B9

C9

0A

CMP #$0A

03BB

90

02

BCC ASC

03BD

69

06

ADC #06

03BF

69

30

ASC

ADC #$30

03C1

D0

E7

BNE WRON

03C3

i

03C3

8A

CKBY

TXA

03CU

F0

12

BEQ BYRDY

03C6

20

D9

03

PKBY

JSR NIB

03C9

E0

00

CPX #00

03CB

F0

0B

BEQ BYRDY

03CD

85

FE

STA LNIB

03CF

20

D9

03

JSR NIB

03D2

0A

ASL

03D3

0A

ASL

03Dl*

0A

ASL

03D5

0A

ASL

03D6

05

FE

ORA LNIB

03D8

60

BYRDY

RTS

03D9

j

03D9

CA

NIB

DEX

03DA

B5

20

LDA BUF,X

03DC

18

CLC

03DD

C9

1*1

CMP #$1*1

03DF

90

02

BCC HEX

03E1

69

08

ADC #08

03E3

29

0F HEX

AND #$0F

03E5

60

EXIT

RTS

03E6

j

03E6

A2

00 INPUT

LDX #00

03E8

20

A5 03

JSR SPTW

03EB

20

CF FF RDON

JSR RDT

03EE

C9

0D

CMP #$0D

03F0

F0

F3

BEQ EXIT

03F2

E0

10

CPX #$10

03Fl*

F0

F5

BEQ RDON

03F6

95

20

STA BUF,X

03F8

E8

INX

03F9

D0

F0

BNE RDON

03FB

»

Not used

03FC

J

Not used

03FD

»

Not used

03FE

»

Not used

03FF

»

Not used

Alphabetical list of label

locations

Label

Location

Label

Location

ADRH

005C

NIB

03D9

ADRL

005B

OPEN

0393

ASC

03BF

PKBY

03C6

BUF

0020

RDON

03EB

BYRDY

03D8

RDT

FFCF

CKBY

03C3

SAVE

F6B1

CKCOL

0371*

SAVIT

039E

CKINS

0360

SAVR

039B

CKX

0386

SPTW

03A5

CRLF

C9D2

START

033A

DISP

031*9

WRASC

03B8

EXIT

03E5

WRBY

03AD

FNLEN

00EE

WRON

03AA

HEX

03E3

WRT

FFD2

INAD

03U7

WRTW

03A7

INPUT

0 3E6

LNIB

00FE

Zero Page locations used

Location

Label

Remarks

0020 to 002F BUF

Input buffer for commands

and

005B

ADRL

Address Lo byte

File

Name

005C

ADRH

Address Hi byte

00E5

EADL

Ending address Lo byte for

SAVE

00E6

EADH

Ending address Hi byte for

SAVE

00EE

FNLEN

File Name length for SAVE

00F1

DN

Device Number for SAVE

00FT

SADL

Starting address

Lo byte for SAVE

00F8

SADH

Starting address

Hi byte for SAVE

00F9

FNADL

File Name address Lo byte

for SAVE

00FA

FNADH

File Name address Hi byte

for SAVE

00FE

LNIB

Low nibble used

in PKBY subroutine

PET Operating System calls used

Label Location

CISCR E23 6

CRLF C9D2

SAVE F6B1

RDT FFCF

WRT FFD2

Listing 2. PET machine-language Mini Monitor program.

90 Microcomputing, October 1980

To avoid errors, use the following guide whenever you want to
save a program using Mini Monitor:

Address

00E5 Enter ending address Lo byte

00E6 Enter ending address Hi byte

00F1 Enter 01

00F7 Enter starting address Lo byte

00F8 Enter starting address Hi byte

00F9 Enter 20

00FA Enter 00

Type S and press RETURN

Type program name and press RETURN

the addresses as necessary. Once these
modifications are made, type S and press
the return key. The display should then look
like this:

00FB XX S 0- Blinking cursor

You may now type the name of the pro-
gram. Up to 16 characters are allowed for
the program name, and quotes are not nec-
essary. After you finish typing the name,
press the return key. You should then see
this message displayed:

PRESS PLAY & RECORD ON TAPE #1

When the save routine in finished, the
tape will stop and the program will exit to
the BASIC interpreter operating system to
give you the familiar READY display. Pro-
grams saved on tape by Mini Monitor can be
loaded or verified in the same way as pro-
grams recorded by BASIC. When saving
programs with Mini Monitor, make sure that
the starting address you enter is less than
the ending address, because the program
does not check this. Otherwise, it will be
necessary to execute a power-off reset of
the machine and your program will be lost.
To save the Mini Monitor on tape, enter the
values in Table 4 into the indicated ad-
dresses.

Once you have Mini Monitor on tape, you
can load it whenever you need to. The pro-
gram is loaded from tape by typing LOAD

and pressing the return key, and then press-
ing the PLAY on tape #1. In a few seconds,
you should see this display:

FOUND MINI MONITOR
LOADING

The program should only take a few
seconds to load before the normal READY
indication appears. Now type NEW and
press the return key to reset the BASIC op-
erating system pointers after the load oper-
ation. You may now enter BASIC programs
as usual or use Mini Monitor.

If you already have a BASIC program in
your machine that you would not want to
lose by typing NEW, and want to load Mini

Monitor, you must first type ?PEEK(124),
PEEK(125) and press the return key. Write
down the values and their respective loca-
tions, then load Mini Monitor in the normal
manner. After the load is finished, type
POKE 124,X:POKE 125, Y, where X and Y are
the values you wrote down for their respec-
tive locations, and press the return key.
Your program is now preserved, and Mini
Monitor is ready for use.

Listing 2 is the machine-language pro-
gram listing and includes an alphabetical
list of label locations, zero-page locations
used and the PET operating system calls
used in the program. ■

RONDURE COMPANY

iS 74

the computer room

ORDERING INFORMATION:

We ship the ame day we receive a certified check or money order. Texas residents
add 5% sales tax. Write for our CATALOG of many parts, terminals, printers, etc.
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SHIPPING INFORMATION:

Modems: $3.00 each; Key Boards $4.00, Power Supply $7.00.

Large Items & Parts: Specify Freight or Air Freight Collect.

Foreign Orders: Add appropriate frelgnt or postage.

We now take Master Charge and Visa orders. Specify full number,
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Printer for your
Microcomputer

USED

POWER

SUPPLY

$15.00

5V at 12 Amp
16V at 6 Amp
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USED

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• Receive only

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• RS-232 interface

• 30 CPS

• Upper & lowercase

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Shipping containers $15.00.

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Will run on serial RS232 port of
most micros including TRS-80.

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12V at 6 Amp
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NEW

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2- 1 5V @ 2.4a $30.00

MICRO SWITCH KEYBOARD

USED BUT LOOKS VERY NICE

ASC II $40.00

(With Print)

MODEM

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ONLY

TESTED

$90.00 Sale

USED FANS

Pin feed— 9” paper

Modem

pickup

GE TERMINET
300 PRINTER

WE HAVE FLAT-PACK
ACOUSTIC

i/ 0 Reader Service index— page 241

Microcomputing, October 1980 91

Merrill Lessley
4903 Nort haven Avenue
San Diego, CA 92110

Easy-to-Build

Computer-Controlled Triac Dimmer

This hardware/software article presents this project in the right light.

Y ou can control the intensity of high-
wattage lamps or the speed of univer-
sal ac motors with your computer by adopt-
ing the circuitry and software in this article.
The dimmer works through conventional
phase-control techniques and, because of a
simple sensing circuit, even adjusts to
variations in line voltage.

Design features include an optically
isolated gating circuit that helps protect
your favorite piece of hardware from
destructive ground loops or other disasters.
Power capacity is determined primarily by
triac selection. Most triacs work well when
attached to an acceptable heat sink and
provided with adequate ventilation. With a
40 ampere triac and convection cooling, the
unit comfortably drives a 200 watt load.

Besides controlling such high-current
loads this dimmer is also a voltage-
controlled device. This means that remote-
control applications can be accomplished
with minimal external wiring. Interfacing is
accomplished through a digital-to-analog
converter (DAC), which transmits a 0 to 5
volt dc signal to the dimmer’s control card.
Final ac output is a function of this signal,
though not necessarily a linear one.

Circuit Description

Before constructing the dimmer, you
should understand how the circuit works.
The schematic in Fig. 1 shows a small isola-
tion transformer coupled to a full-wave
bridge formed by diodes D1, D2, D3 and D4.
The unfiltered output from this bridge acts

as a gating signal for the zero-crossing
detector created by Q1. Whenever the out-
put from the bridge approaches a zero
potential, Q1 produces a narrow and
positive pulse, which is inverted by Q2. One-
hundred and twenty such pulses occur
every second.

This pulse chain continually resets the
ramp signal generated by C3 charging itself
through R5. Buffering this ramp is the
source follower formed by operational
amplifier (op amp) A in IC1. An oscilloscope
connected to test point B reveals a linear
ramp being reset each time the ac line
signal crosses its zero point (Photo 1).

The ramp signal from op amp A travels to
the non-inverting input (pin 10) of a voltage
comparator (op amp B). This comparator

D 5

92 Microcomputing, October 1980

Photo 3. Time — 2ms/C. Volts— 2 mV/C. Photo 4. Time—2ms/C. Volts — 50 V/C.

swings into positive saturation as the ramp
signal reaches a level almost equaling the
reference voltage at pin 9. Resetting the
ramp forces the comparator back into
negative saturation. The width of the output
pulse at pin 8, therefore, is determined by
the voltage applied to pin 9. Q3 inverts this
variable width pulse and correspondingly
turns the LED in IC2 on and off.

To illustrate the importance of this
variable width pulse, consider the following
examples referenced to the positive half of
the ac line signal. A voltage level at pin 9
slightly less than the ramp’s maximum
amplitude produces a narrow pulse at test
point C (Photo 2). The output of this pulse is
timed to occur as the positive swing of the
sine wave approaches its zero potential.
Lowering the voltage at pin 9 produces a
wider pulse at the comparator’s output
(Photo 3), whose leading edge occurs
earlier in the sine wave’s positive swing.

The sine wave’s negative half duplicates
this pulse pattern.

Pulses from the comparator turn the LED
on and off and, therefore, trigger the light-
activated silicon-controlled rectifier
(LASCR) in IC2. This LASCR, working in con-
junction with a full-wave bridge (diodes D6,
D7, D8 and D9), helps to generate a series of
pulses that eventually reaches the triac’s
gate through R18. And this finally switches
the triac on and off so that current flows
through the load.

In summary, the amount of current pass-
ing through the load relates directly to the
triac’s rapid on-off action. A low-level signal
at pin 9 triggers the triac early in the sine
wave when more current can ultimately
pass through the load. Conversely, increas-
ing the dc potential at pin 9 reduces the
triac’s on time and decreases its output
capability.

Photo 4 illustrates how a triac’s switch-

ing action literally slices up the ac sine
wave. The pulse chain producing this exam-
ple is sampled in Photo 2. In this case, the
triac is driving a 300 watt incandescent
load at 80 volts true rms.

At this point, the circuit represents a sim-
ple voltage-controlled dimmer. Unfor-
tunately, an inverse relationship exists be-
tween control voltage and actual dimmer
output. Solving this inconvenience requires
the addition of op amp C. Output from this
amplifier equals the voltage at pin 12 minus
the voltage at pin 13.

The circuit reveals that the minimal
signal at pin 12 must normally be slightly
less than the ramp’s maximum amplitude.
RIO provides this signal and corresponding-
ly acts as the dimmer’s idle or low-end ad-
justment: The dimmer will start to idle if 0
volts appear at pin 13 and RIO supplies pin
12 with a dc signal just below the ramp’s
maximum amplitude. Raising the voltage at

Microcomputing, October 1980 93

pin 13 increases the dimmer’s output. Op
amp D, configured as a source follower, buf-
fers the dc input signal at pin 3, IC1.

By adding op amp C, the dimmer’s output
becomes a positive function of control
voltage input. At 0 control volts, the dimmer
idles or remains off; at 5 control volts, the
dimmer reaches full power. Op amp C fur-
ther serves as a sensing circuit along with
R6, R7 and R8, all of which monitor line-
voltage variations.

An appreciable drop in line voltage
decreases the dc potential at pin 12 via R6
and R8. And, because of the summing mode
of op amp C, the voltage at pin 9 is also
reduced. It is this reduction that forces the
triac to advance its firing angle and thereby
provide compensation for apparent line
loss. Incidentally, R8 sets the sensitivity of
this circuit.

This means that computer control of the
dimmer’s output can be achieved by con-
necting a digital-to-analog converter to the

Fig. 2. Digital-to-analog converter circuit.

dimmer’s control-voltage input. Since this
arrangement only requires two wires, you
can easily install the dimmer in remote loca-
tions. Almost any DAC will do, providing it
outputs a 0-to-5-volt signal. The converter in
Fig. 2 works well for general applications
and is driven by a simple PIA port. Note the
PIA’s inverted output. On my system, this
inversion helps because a manual reset
drives the PIA outputs high. Inverting the
port adjusts the DAC’s output to 0 volts
after each reset.

Construction

Constructing the dimmer is simple. You
can print a PC board from the actual-size
foil pattern in Fig. 3; Fig. 4 details the cor-
rect parts layout. An assembled board is
pictured in Photo 5, and Fig. 5 presents the
final wiring diagram.

Avoid connecting the dimmer’s power
supply common to the ac line ground. Also
remember to polarize the plug by connect-

ing the black wire to the hot side of the ac
line and the white wire to the neutral side.
The all-important safety ground, the green
wire, must be attached to the dimmer’s
metal enclosure. Follow this procedure to
protect both you and your equipment from
dangerous electrical shocks.

Take special care to locate the dimmer’s
power outlet on the neutral side of the triac
to provide a specific safety measure intend-
ed to reduce the possibility of inadvertent
shock. Wiring the plug into the triac’s hot
side increases the danger of electrical
shock because the full ac line power is
always just a fingertip away, even with an
inactive or idling triac. Placing the plug on
the neutral side forces both sides of the
outlet to remain essentially at ground
potential whenever the triac is off or in a
high-impedance state.

The triac’s rapid on-off switching pro-
duces current surges that generate signifi-
cant radio-frequency interference (rfi). Long

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94 Microcomputing, October 1980

Photo 5. An assembled circuit board.

circuit wires act as transmitting antennas
for such noise. To counteract this, shield or
twist the triac’s gate leads and keep them
short. Rfi can also travel down the ac line.
This can be largely corrected by utilizing a
100 mH choke (LI) and a bypass capacitor
(C5).

Testing and Adjustment

Test and adjust the dimmer before you
connect it to your computer. Start testing
and adjusting procedures by centering pots
RIO and R22. Connect an ordinary 60 watt
lamp to the dimmer’s output. Plug the dim-
mer in and adjust RIO until the lamp just
barely begins to glow. Unplug the dimmer
and replace the lamp with a load approx-
imately equal to 50 percent of the dimmer’s
intended capacity. Apply power and re-
adjust RIO.

If you have a spare 5 volt power supply,
the next step will be easy. Just attach a 10k
potentiometer across the supply leads. Ad-
just the pot for a 2.5 volt output. Connect
this signal to the dimmer’s control voltage
input and adjust R22 for 79 true root mean
square (rms) volts across the load. Making
this adjustment requires a true rms meter;
ordinary ac meters are designed to measure
relatively smooth sine waves and not the
fragmented signals produced by triacs.

Producing the 79 volt true rms value at a
2.5 volt control signal helps produce a
satisfactory visual curve for the dimmer.
Because the human eye perceives light in a
somewhat logarithmic fashion, the smooth
control of incandescent loads requires that
a nonlinear relationship exist between con-
trol voltage and true rms output.

Put another way, calibrating in this man-
ner forces the dimmer’s luminary output to
appear as if it were actually a linear func-

tion of control voltage input. A more com-
prehensive explanation of this
phenomenon is beyond the scope of this ar-
ticle. You should also realize that this ad-
justment slightly limits the dimmer’s
highest output to about 115 volts, an in-
significant loss with incandescent loads.

To calibrate without a true rms meter, in-
crease the control voltage to 5 volts and at-
tach a standard ac meter across the load.
Turn R22 fully clockwise. The meter should

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iS Reader Service index — page 241

Microcomputing, October 1980 95

Fig. 3. Full size PC board foil
pattern.

read between 115 and 120 volts. Now slowly
rotate R22 counterclockwise until the meter
indicates a 2 volt decrease from the
previous reading. A fairly accurate curve
can be achieved through this alternate pro-
cedure.

Alignment for universal ac motors is
largely a matter of personal preference.
Just remember that RIO adjusts the dim-
mer’s idle level, and R22 determines its
maximum output. These controls can also
establish a confined operating range for the
dimmer. RIO, for example, might be set so
that the dimmer’s output will never fall
below half power. Computer control would
then range from half to full power. Also,

when working with an electric motor, avoid
overheating conditions that occur when a
motor stalls or operates too slowly.

After testing and alignment, check again
for wiring errors that might produce ground
loops. Use an ohmmeter to make certain
that no conductive paths exist between the
ac line plug pins and the control voltage
wires. If the dimmer passes this test, it can
be attached to the computer’s DAC.

Fig. 6 illustrates a convenient way of mak-
ing this connection. Flexibility is gained
through SI, which affords you the oppor-
tunity to select manual, computer or exter-
nal control. Making this connection pre-
pares the dimmer for actual software im-

plementation.

Software

My system is an odd blend of parts, but,
in general, it likes to assume the identity of
a 6800-based unit with a MIKBUG monitor.
And, as I’ve said, the computer’s DAC is
driven by a PIA at $8008 and $8009.

Systems configured like this can use
Listing 1 to program a 6820 PIA to act as an
eight-bit latching port. Load the program
and place the hexadecimal data to be trans-
mitted into memory location $000D. After
this, load the starting address ($0000) into
$A048 and $A049. Type G, and the port will
respond by sending the DAC its data.

96 Microcomputing, October 1980

Yes, I want to LEARN Level II!

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92020

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copies of LEARNING LEVEL

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iS Reader Service index— page 241

Microcomputing, October 1980 97

0000

7F

8009

CLR

$8009

0003

86

FF

LDA

A

#$FF

0005

B7

8008

STA

A

$8008

0008

86

04

LDA

A

#$04

000A

B7

8009

STA

A

$8009

0000

86

XX

LDA

A

#$XX (DATA)

000F

B7

8008

STA

A

$8008

0012

3F

SWI

Initialize PIA into Latching
Port

Load and Send Data

(Change to 39 for User Routine)

Listing 1. PIA routine.

10 REM DIMMER CONTROL ROUTINE

20 REM ESTABLISH USER PROGRAM LOCATION

30 POKE (103,30)

40 POKE (104,175)

50 REM NOW INPUT DIMNCR LEVEL
60 INPUT "LEVEL" ,X
70 IF X > 255 THEN 60
80 REM INVERT THIS VALUE
90 LET Z=255-X
100 POKE ( 7869, Z )

110 REM CALL USER ROUTINE
120 LET A=USER(Z)

130 REM PRINT D IMMER LEVEL ON SCREEN

140 LET Q=255-A

150 PRINT

160 PRINT Q

170 GOTO 60

180 END

Listing 2.

Relocating the routine is no problem, but
remember to clearly identify the data byte’s
storage location. For PIAs not at $8008,
alter the program’s address calls. Notice,
too, that the circuit in Fig. 2 inverts the PIA’s
output, which means that data byte must be
a complement value.

If you change the last instruction of the
listing to RTI (39), the routine will work nice-
ly in the user space of SWTP BASIC. To pro-
gram dimmer output, poke an appropriate
decimal value (0 to 255) into the data loca-
tion and jump to the user routine. Control
returns to the BASIC interpreter after the
PIA has latched. Dimmer output remains

stable until another command reactivates
the DAC.

Listing 2 is an example of how POKE
commands can interact with Listing 1. In
this case, the program has been relocated
to $1EAF, the beginning of user space in
SWTP BASIC (ver 2.0). The first two instruc-
tions poke the address of the user routine
into memory locations $67 and $68. This
tells the interpreter where to transfer con-
trol when using the user command. The in-
put instruction requests a dimmer “level,”
which must be entered in decimal format (0
to 255). This value is inverted and poked into
$1EBD. The dimmer level then appears on
the terminal’s screen, and the program re-
quests another input.

User routines can be frustrating, espe-
cially when coupled with POKE instruc-
tions. One mistake can cause the inter-
preter to self-destruct or damage the user
program. Some protection can be afforded
by carefully defining user space in advance.
With SWTP BASIC, for example, start the
process by initializing the interpreter to

UCSD* System for TRS-80 Model 11+

The most portable operating system now supports FORTRAN. Pascal and/or FORTRAN modules are compiled in universal P-code, so they
can run on most microprocessors, often without recompiling. Programs execute up to 10 times faster than comparable BASIC programs, and
use much less memory. Ready to run on TRS-80 Model II (64K).

FEATURES

■ Interactive operating system-dynamic
overlays, disk file handling, run-time sup-
port and block I/O routines.

■ Fast, one pass compilers.

■ Two Editors-one screen oriented for pro-
gramming and text editing, one character
oriented for hard copy terminals.

■ File handler to manipulate disk files.

■ Macro-assembler that produces code for
linking with Pascal or Fortran programs.

■ Linker for link-editing of object and as-
sembly code modules.

■ Library of program modules and utilities.

PLUS, from PCD Systems

■ Disk formatting program to initialize dis-
kettes in single or double density formats.

■ Configuration program for serial I/O.

■ Disk-set program to permit separate as-
signment of density and format charac-
teristics for each disk drive.

DOCUMENTATION

■ UCSD System Manual (400 pages).

■ Beginner's Guide To UCSD Pascal.

■ Pascal User Manual & Report.

■ Fortran User's Manual with Fortran
systems.

PRICES

■ UCSD System with Pascal Compiler $350
with Pascal and Fortran Compilers $500

■ Fortran Compiler alone

(requires Version 1 1.0) $200

■ P-Code Interpreter alone

(either LSI-11 or Z-80) $ 85

Optional Utility Programs

■ CP/M* to Pascal file conversion $ 50

■ TRSDOS + to Pascal file conversion $ 50

■ Z-80 Disassembler/Dump program $ 50

ALSO AVAILABLE

■ UCSD System for MINC § or PDT S .

■ Z-80 Adaptable System (you write BIOS).

■ UCSD System for CP/M environments.

PCD Systems is a licensed distributor of the
UCSD System for Pascal and Fortran. Dealer
inquiries are invited.

PCD Systems, Inc.

PO Box 143 PennYan, NY 14527 315-536-3734

’‘Trademark of the Regents of the University of California f Trademark of Tandy Corporation ‘Trademark of Digital Research ’Trademark ot Digital Equipment Corporation

98 Microcomputing, October 1980

is 240

2JC

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30AB7

verify the cassette load. After this, manual-
ly reset the computer and allocate user
space by placing the desired byte in $104E.
Complete the sequence by exercising a
hard rather than a soft start. This procedure
forces BASIC to recognize the new param-
eters that distinguish user space from
memory dedicated to normal variable and
program storage.

The principles expressed in these ex-
amples can be applied to more complex
programs that simultaneously control
several dimmers. To do so, however, re-
quires that the detailed work of controlling
and selecting dimmers must be ac-
complished by efficient user routines. The
BASIC interpreter may be easy to work with,
but, in general, it is too slow to directly im-
plement complex and fast-shifting lighting
effects.

Conclusion

Here are some brief comments concern-
ing the design philosophy surrounding this
dimmer. One approach was the creation of
a purely digital dimmer with the ability to in-
terpret serial or parallel data commands;
for certain applications this seemed keenly
advantageous. In my case, however, a mix-
ture of digital and linear techniques worked
best. The need to utilize long remote-control

lines was the deciding factor. To run 16
analog lines from a computer is infinitely
easier than extending and decoding 16
serial lines.

Also, consider the problems associated
with implementing manual override when
using serial data. At least the linear circuit
makes manual or independent control easy
to work with. You can even intermix manual
and computer control by presetting the in-
dependent potentiometer and driving it with
the computer’s DAC. Try such intermixing

with an ACIA or UART.

In retrospect, then, this article shows
how digital and linear techniques can
merge to produce a versatile tool with many
applications.!

The author wishes to thank the San
Diego State University Foundation,
which helped support this work through
a faculty grant-in-aid.

D1 through D9- 1N4004 diode

R15- 100,000 Ohms

Cl — 470uF 50V electrolytic capacitor

R16- 47,000 Ohms

C2, C3.C4-.1uF 50V ceramic

R17-330 Ohms

C5 - ,1uF 600V

R18 through R21 - 100,000 Ohms

R1 -1000 Ohms

R22— 100,000 Ohms PC trimmer

R2-1000 Ohms

R23— 68,000 Ohms

R3-4700 Ohms

Q1, Q2-2N2222 npn transistor

R4-1000 Ohms

Q3-2N3567 npn transistor

R5- 220, 000 Ohms

Q4-2N5445 40A triac, or T6420D

R6- 10,000 Ohms 1%

(isolated stud 40A triac)

R7- 100,000 Ohms

LI — IOOuH choke (current rating

R8-470 Ohms

dependent upon triac selection)

R9 — 1500 Ohms

IC1 — LM324 quad op amp

R10 — 2000 Ohms PC trimmer

IC2 — LM340T-12, + 12V regulator

R1 1 - 100 Ohms

IC3 — MCS2400 optical coupler

R12- 100,000 Ohms

T1 — power transformer, 12.6VAC

R13-120 Ohms

300mA secondary, PC mount

R14-560 Ohms

(Radio Shack 273-1385)

Parts list. All resistors Va watt 10 percent, unless otherwise noted.

Reader Service index — page 241

Microcomputing, October 1980 99

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r

William E. Shawcross
Roger W. Sinnott
Sky Publishing Corporation
49 Bay State Road
Cambridge, MA 02238

S ky and Telescope is a monthly
astronomy magazine with a circulation
of 75,000. Each month we generate 65,000
mailing labels, an average of 10,000 renewal
notices and a number of listings and mail-
ing reports. All of this has to be done in less
than a week. On top of this, there are typi-
cally 5000 changes and additions to the file
each month.

Could a small computer handle this job?
We wondered. One of us (Bill) had long been
interested in the possibility, ever since coor-
dinating the changes from a manual stencil
system to a big IBM computer at a service
bureau in 1969. But the hardware to do it
ourselves remained too expensive until the
microcomputer revolution of the mid-1970s.

Out of the Blue

Roughly three years ago, Ohio Scientific
introduced the C3-B, a rack-mounted micro-
computer with dual eight-inch floppy-disk
drives and a 74-megabyte Winchester hard
disk. Our data base, then almost ten mega-
bytes, had been too large for floppies, but
the Winchester was just right. We were for-
tunate to have an OSI dealer in Cambridge,
and so we visited Robert Rivers at the Com-
puter Shop. A demonstration convinced us
that the machine had enough speed and
capability for our needs.

And so a year ago, after 1 1/2 years of
preparation, we transferred our mailing list
from the IBM 360/30 at the service bureau to
our own in-house OSI computer. We were
looking primarily for convenience; we didn’t
want to rely on the mails to get our
subscription material (punched paper tape)
back and forth from the service bureau.
With our own computer, we would be able
to put new subscribers on the system the
day their names came in. We could also let
the computer do a number of office jobs
that for years we had done by hand.

The major unknowns were reliability and
file backup, which are critical in converting
to an in-house computer. At the time, car-
tridge-tape backup units were not available,
and standard tape drives with formatters
cost as much as the C3-B.

A magazine article on computer repair
led us to the solution of both reliability and
backup -get two identical computers. This
would let us keep the files in separate
places (in our case, in separate buildings).
Regular copying from one machine to the
other would keep the backup file within a
month of being up-to-date. And circuit
boards could be swapped easily in a pinch.

On this basis we took the plunge. We

102 Microcomputing, October 1980

Software Problem and Solution

The first of these was learning, in minute
detail, how the Microsoft BASIC interpreter
interacts with large files on the OSI

The service-bureau computer room, with numerous tape drives, where the Sky and Tele-
scope subscriptions were processed between 1969 and 1979. It is operated by Computac,
Inc., in West Lebanon, NH. The Sky and Telescope circulation department prepared
punched paper tape (on a Friden Flexowriter) that was delivered to Computac weekly,
containing all the names of new subscribers or renewals in machine-readable form.

Changes are input, sorted and then pro-
cessed against the tape. A new tape is
made (on another tape drive) incorporating
the changes. Such sorting and merging,
however, is utterly impractical on a micro
with a BASIC interpreter. We guessed that
to merge two files to a third place on the
disk would take us at least 20 hours for
each weekly update.

A double-size file that stays put on the
disk was our solution. Here, on the average,
every other record is a blank, or “hole.”
Since our mailing list is in zip-code order,
and names are alphabetical within each zip
code, a binary search of about 17 seeks will
find a record that needs revising in about
six seconds. If a new subscriber is to be in-
serted, the same amount of time will locate
the appropriate hole. Occasionally, a bit of
spreading is needed to make room for the
new person, if some records are bunched
together. Our updating program does this
automatically.

In essence, we have an on-line system
that is run from floppy disks rather than
directly from the keyboard. Since an audit-
trail report is needed for all file transactions
to satisfy the Internal Revenue Service and
the postal system, putting the work on a
floppy first means that the line printer does
not have to be running except when the
floppies are being processed against the
master file (about 30 minutes, at the end of
each day’s work). And since the data base is
copied to the backup computer only once a
month, we save four weeks of floppies in
case the primary computer should ever fail.
A floppy-based system thus has many im-

The new OSI C3-B computer, Printronix 300 and a Soroc terminal by which the same job is
now done more efficiently in-house at Sky and Telescope. (Photos by Dennis diCicco)

bought the first computer in August 1978,
and the second one the following February.
We ordered a Printronix 600 line printer (600
lines per minute) but eventually had to set-
tle for a Printronix 300. We bought a used
Centronics 100 printer with the first com-
puter so we could do development work.
Our suite of equipment was rounded out
with a Tab miniburster (with slitter), Tab
decollator, a Hazeltine 1500 terminal and
three Soroc IQ-120 terminals. The total cost
was around $45,000.

Getting the equipment was just the start.
The real effort had to go into programming,
which proved very time-consuming.

Neither of us was completely new to
computers. Bill had gone to programming
school and had put together one of the very
first Altair 8800 kits. Roger had bought the
Altair from Bill and learned North Star
BASIC on it. Bill took over project manage-
ment and definition, and Roger gave up
some of his editorial duties so he could
spend about half his time on programming.
The project took a whole year.

In the late 1960s, Bill had helped define
the functions of the mailing package used
by our service bureau, and therefore knew
what it did and how it did it. We assumed it
would be a fairly easy matter to duplicate
the functions of the big computer. But there
were two areas in which we badly under-
estimated how much work we had to do.

74-megabyte disk. For most hacking this is
not a serious matter, but when you’re trying
to design as efficient a system as possible,
everything counts. For example, Roger
eventually found a way of copying large
files that runs three times faster than the
copying utility supplied by OSI.

On a large mainframe computer, a maga-
zine subscription list is usually kept in
serial order on a reel of magnetic tape.

Microcomputing, October 1980 103

portant advantages.

File Transfer

Our second major problem was getting
our data base out of IBM-land and onto our
own machine. We thought of a number of
possibilities: punched paper tape (16 miles
of it), the telephone (90 hours of long-
distance charges), a 1/2-inch computer tape
(rental drives not readily interfaced to OSI)
and rekeyboarding all the names and ad-
dresses (1000 hours for a good typist).

Floppy disks seemed the only possibility,
but there was a catch here too. Our service
bureau could supply the file on eight-inch
floppies, recorded in the standard IBM for-
mat of 128 bytes per sector, 26 sectors per
track. OSI uses the same hardware but a dif-
ferent format. In fact, OSI’s format seems to
be unique in the industry, so buying soft-
ware from other sources is difficult.

Here Roger’s Altair came to the rescue.
We bought a Tarbell S-100 disk-controller
board and attached the OSI floppy drives to
the Altair. A word of caution: OSI supplies
the -5 volts from the CPU power supply
through the connecting ribbon cable, rather
than from the floppies’ own power supply.
This caused us a major headache until
Roger traced the problem down.

An assembly-language routine for the
Altair read each track-size block of 13
names and addresses from a floppy into
RAM, inserted ASCII carriage returns in all
the right places and sent them out a serial
port at 9600 baud to the OSI computer.
There, a BASIC program accepted each
character string in turn and sent a hand-
shaking character back to the Altair when it
was ready for the next string. (This was
necessary because the Microsoft BASIC in-
terpreter seemed to take unpredictable
amounts of time to assimilate the strings as
they came in.)

When 13 names and addresses had been
transferred, the OSI computer paused for
half a second to store them sequentially on
the hard disk and asked for more. The Altair
then read in the next higher track, and so
on. Proceeding in this manner, the two com-
puters worked without intervention for
about seven minutes to transfer all 949
names on a floppy. It was a complicated
operation, to be sure, but when things were
going smoothly it was spectacular to
watch!

In this way the file was transferred, at a
mere cost of $250 for the Tarbell board and
$200 to the service bureau to have them put
the file on 69 floppy disks we had provided
(and which we are now reusing for our daily
work). We did the transfer when our other
software was essentially done, so that we
could try out our own system in parallel with
that of the service bureau for a couple of
months to be sure the results were the

same. Six months is usually recommended,
but the duplication of several thousand
transactions a month was putting a severe
strain on our circulation department of just
three people. Fortunately, all went well, and
we were able to complete the changeover in
November 1979. We have been self-suffi-
cient ever since.

System Operation

As it now stands, our system lets us enter
on floppies new subscriptions, renewals,
address changes and deletions. This can be
done with more than one terminal at once, if
necessary, thanks to the OSI time-sharing
option. The operator can request adhesive
mailing labels to be printed so the current
issue of the magazine can be sent im-
mediately -something that used to be
done by hand.

We also have two programs for locating
particular people in the file. The first uses
the same binary search technique men-
tioned earlier. If you know a subscriber’s zip
code and a few letters of the last name, the
record can be called up in six to seven
seconds. (Sometimes the program tells you
that the name is not currently in the file.)

The second method sweeps through the
file from any starting place to the end, look-
ing for a specified character string of up to
32 characters. Thus, for example, If
Ebenezer Jones lives somewhere in Califor-
nia, it makes sense to use his first name as
the search string and to start looking at zip
code 90000. All too often, a person sends in
a change of address with the old address
missing! This kind of search, from one end
of our 23 megabyte file to the other, can
take as long as 18 minutes.

Along with renewal notices and mailing
labels, the system produces a monthly
geographical breakdown by zip code, used
for postal reports, and various file dumps.
We also make a printout each month of the
names of people who decided not to renew;
this list can be used at a later date, in case
we want to do a selective mail campaign.

We still need to speed up the file transfer
between the two machines. This procedure
now takes about 3 1/2 hours at 19,200 baud
over a 100-foot coaxial cable. The OSI serial
ports can be jumpered for 250,000 or even
500,000 baud as soon as we find time to
write the assembly-language handlers for
synchronous data transfer. This should cut
the time to under half an hour for the 23
megabytes.

Extraterrestrial Applications

We have found other uses for all this
computing equipment. One nice feature of
the Printronix 300 is its ability to serve as a
plotter. Roger has written a program that
prints out a chart showing the motions of
Saturn’s moons; all we do is add labels and

send it off to the camera department for use
in Sky and Telescope. Most days of the
month, the second (backup) computer is
available for use by our scientific staff.

Another area in which the computer
helps is our advertising billing and ac-
counts receivable -a sizable portion of our
income. For this we bought the OSI Data
Management System nucleus and modified
parts of it to print our bill forms. This soft-
ware may not be the fastest or most elegant
in the world, but it is dependable, easy to
work with and reasonably priced ($300). It
has general-report writers and file handlers,
allowing easy maintenance of a small ad-
vertiser mailing list. We also have a
separate dealers file for addressing the new
price lists of the books we sell.

A Successful Flight

We have faced few difficulties since the
changeover — and none that has caused us
to miss a schedule. This is probably due in
large measure to the fact that we know a lot
about our equipment, and everything there
is to know about our subscription pro-
grams. The usual memory glitches (chips
go bad from time to time) and a dead LED in
a floppy drive (it couldn’t find the index hole)
are the only equipment failures we have had
in two years.

We had some strange error messages
and the like when the computer-room
temperature rose above 80 degrees
Fahrenheit. The equipment behaves
strangely at such temperatures, so we now
use air conditioning when needed to keep
the room from getting warmer than 75
degrees.

Also, though the OSI manuals warn
against shutting off the CPU before the
hard disk, we have inevitably done this ac-
cidentally a couple of times. Sometimes it
doesn’t have any effect, and other times it
wipes out the operating system on the disk
and forces us to get the backup floppy out
of a vault. (Why can’t the equipment be
designed so that it doesn’t matter how you
shut it off?)

A dependable dealer nearby is a great
help. Bob Rivers at the Cambridge Com-
puter Shop and Ed Craddock at the Boston
branch have helped us often both with sug-
gestions and new software releases.

Make a careful estimate of how long it
will take to program an application and then
double or triple the time. Don’t get yourself
into a corner with rigid scheduling -equip-
ment is seldom delivered as soon as you ex-
pect, and software is almost never released
on the date first announced. Anticipate be-
ing discouraged and ready to give up every
now and then, particularly during the de-
velopment phase.

And, above all, enjoy the satisfaction of a
difficult project finally brought to fruition. ■

104 Microcomputing, October 1980

Now You Can Put a
TRS-80 Computer

Tn Va«i< Pnrlrofl

WEIGHS ONLY 6 OUNCES!

Another Radio Shack Personal Computer Breakthrough!

Now you can carry computer
power wherever you go. And with
the TRS-80 Pocket Computer, you
can create your own programs or
purchase ours. These are available
now: Civil Engineering, Aviation,
Business Statistics, Games, Per-
sonal Finance, Math Drill, and Real
Estate.

Look At These Exciting Features!
57-key alphanumeric keyboard.
Big LCD display that scrolls left and
right for program line entry and ed-
iting, and steps up and down for
program listing. Programmable in
an enhanced, easy-to-leam BASIC
language. Built-in arithmetic func-
tions including trig and inverse trig
(with readout in degrees, radians
or gradians) log, exponent, square
root, angular conversions, integers
and absolute values. Accuracy is to
10 digits and it can handle 2 -digit

exponents. With array and 7-char-
acter string-handling ability you’ve
really got a handful of computa-
tional power!

Programs and Data Retained in
Memory When Power Is Off! The
1424-step memory is automati-
cally partitioned for program and
data storage. There’s a 26-data ele-
ment memory and 48-step reserv-
able memory.

Available Now! Exclusively at
Radio Shack stores, dealers and
Computer Centers. Complete with
carry case, manual, batteries.
Hurry, because everyone will want
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And what could make a better or
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Nothing Else You Can Put In
Your Pocket Can Do All This!

10 Print "SHELL METZNER SORT": FOR X = 1 TO 100:

PAUSE "DATA ITEM #":X:INPUT A(X + 100): IF A(X + 100
)<0 GOTO 25
20 NEXTX
25 M = X - 1

30 M = INT(M/2): IF M = 0 GOT0 107
40J = 1:K = X- M-1
50 I = J

60 BEEP 1 : L = I + M: IF (A(l + 100)< = A(L + 100))

GOTO100

70 T - A(l + 100): A(l + 100) = A(L + 100):

A(L + 100) = T: I = I M: IF l<1 GOTO 100
90 GOTO 60

100 J = J + 1: IF J>K GOTO 30
105 GOTO 50

107 BEEP 5: INPUT "PRESS ENTER FOR LIST"; A
110 FOR I =1T0X - 1: J = I + 100: PAUSE "DATA ITEM #";
USING "####"; I; ” ”;A(J): NEXT I

I SendMe YourlREE
TRS-80 Computer Catalog!

Radio Shack, Dept. 81-A-23
I 1300 One Tandy Center
Fort Worth, Texas 76102

NAME

TITLE

FIRM

Radio /haek

The biggest name in little computers®

STREET

CITY

STATE

ZIP

PHONE

’Retail prices may vary from store to store. Optional Cassette
Interface, $49. Minisette-9 Cassette Recorder. $79.95.

A New Branch
On the Family Tree

National Semiconductor sprouts the NSC800.

Ken Barbier
Borrego Engineering
PO Box 1253

Borrego Springs, CA 92004

T he recently announced
NSC800 microcomputer
system from National Semicon-
ductor represents a new branch
on the 8080 family tree. It com-
bines the best features of the
8080, the 8085 and the Z-80 with
a new fabrication technique
called poly CMOS. This pro-
prietary new process (tagged
“P 2 CMOS” by National) com-
bines the speed of NMOS cir-
cuits with the low power con-
sumption of CMOS.

Initial offerings in this prod-
uct line include the NSC800
CPU, the NSC810 RAM-l/O-timer
and the NSC830 ROM-I/O. All
three are constructed using the
same low-power P 2 CMOS. This
chip set can be combined into a
complete controller consisting
of the three 40-pin packages, a
crystal, one resistor and a
capacitor.

This combination provides 2K
bytes of ROM, 128 bytes of RAM
and 32 bits of I/O that can be pro-

grammed to be either inputs or
outputs. Power required can
vary from 3 to 12 V dc, and the
low power drain would enable
full-speed operation for two
days from a battery back-up
system consisting of three
D-size nicad batteries.

The familiar features of the
new National microprocessor
system should appeal to its
users. The CPU uses the pin-out
of the Intel 8085 and executes
the entire Z-80 instruction set.

Rather than trying to
establish a new dynasty of its
own, National wisely copied the
best features of earlier
members of the 8080 family.
This means that users of the
earlier 8080, 8085 and Z-80 will
be instantly able to design hard-
ware and write software for the
new microprocessor. Existing
development systems, assem-
blers and PROM programmers
can supply all the support re-
quired for this new system.

The NSC800 chip set and
user’s manual were not
available as this was written,
but the prospective user can
gain valuable insight into
techniques usable with the
NSC800 by looking back at its
predecessors. The reasoning

behind National Semiconduc-
tor’s decision to merge the pin
configuration of the 8085 with
the instruction set of the Z-80
unfolds as we look back at the
history and evolution of the 8080
microprocessor family.

The Roots: Intel’s 8080

The 8008 microprocessor was
relatively insignificant com-
pared to its big brother, the
8080. Since its introduction, the
8080 and its descendants have
become the standards of the
microprocessor industry. If you
don’t want to accept that fact,
just look at the relative amounts
of available software and the
number of different computer
systems based on the 8080 fami-
ly, although other hnicros may
provide features lacking in the
’80 family.

The 8080 was not the
ultimate. To implement any
8080-based system, the 8080
central processor (CPU) has to
be supported by a bi-phase,
high-level clock generator; a
system controller; and bus buf-
fers. In spite of this, however,
new products are still being in-
troduced based on the 8080,
even though its successors pro-
vide greatly expanded capability

combined with reduced com-
plexity.

To eliminate some of the
8080’s support requirements, as
well as add expanded capabili-
ty, Zi log’s Z-80 and the Intel 8085
have since appeared. These
micros are upward compatible
with the ’80, executing the same
instructions as the 8080 and
adding instructions of their own.

The Z-80 Instruction Mountain

The original designers of the
8080 used 244 out of the 256
possible combinations of eight
bits as the basic instruction set.
This left the door open a crack
for the Zilog Z-80 designers to
take advantage of the 12 un-
implemented operation codes
(op codes) to greatly expand the
instruction set. With a couple of
exceptions, this required a dou-
ble level of instruction de-
coding.

The first eight-bit byte of the
expanded instruction set tells
the decoder that it will have to
fetch an additional eight bits
from the next memory location
and decode that second byte to
determine the desired opera-
tion. In this manner, 8-, 16-,
24- and 32-bit op codes have
been implemented in the Z-80, at

106 Microcomputing, October 1980

the expense of additional
memory fetches and execution
time. Where speed is critical, as
in servicing interrupts, the Z-80
executes two new single-byte in-
structions, the register ex-
changes EXX and EX AF.

The new multi-byte op codes
implement functions that would
have required many instruction
and data fetches anyway, such
as block data moves and bit
manipulations, so there is still a
net gain in efficiency in spite of
the multiple-level decoding re-
quired by this technique.

While the major advantage of
the Z-80 over the 8080 is the ex-
pansion of the instruction set, it
also provides simplified inter-
facing to the outside world. Only
a single-phase clock is required,
and more usable bus control
signals are provided by the CPU.

The 8085

Perhaps in answer to the ad-
vent of the Z-80, Intel next in-
troduced the 8085 microproces-
sor. At first glance, the ’85
almost seems to be a step in the
wrong direction. Adding only
two instructions to the 8080 op
code set, it is a far cry from the
Z-80’s mountain of new op
codes. The 8085 shines in the

simplicity of implementing
small systems, such as dedicat-
ed controllers.

The 8085 doesn’t require an
external clock generator. Simply
connect a crystal across pins 1
and 2 to operate the ’85. It even
provides buffered clock output
for other uses, such as supply-

ing a bus clock or an input to a
baud rate generator. If crystal
timing accuracy is not required,
substitute ten cents’ worth of
resistor and capacitor for the
crystal.

For controlling the real world
in real time, the ’85 provides five
different hardware interrupts
accessible through individual
pins and, in addition, can still
support the multilevel priority in-
terrupts that are implemented in
8080 and Z-80 systems (as well
as 8085 systems) by the addition
of a separate interrupt con-
troller. If five levels of hardware
interrupt are enough for a par-
ticular application, however, all
are instantly available at
separate pins on the 8085.

Additional simplification is
provided by the inclusion in the
’85 of “serial” input and output
ports — in actuality, a one-bit in-
put and a one-bit output port. In
many applications, a “software
UART” program can be written
to make use of the serial I/O
lines and emulate the hardware
baud rate generator, crystal and
UART chip usually required for
communication with a terminal
device.

Several of the functions of the
8080’s system controller are im-
plemented internally in the ’85,
providing signals for controlling
the flow of data to and from

memory and I/O devices. If more
detailed CPU status information
is required, status lines are also
available, as was provided by
the 8080’s controller.

If the ’85 is used with older
8080-style peripherals or
memory, these status lines may
have to be decoded to provide
full 8080 compatibility. How-
ever, all newer memory and pe-
ripheral controllers are fully
compatible with the ’85 bus con-
trol signals, and the status out-
put pins can be ignored in new
designs. The one exception is
shown in Fig. 1, where the
status lines and a single NOR
gate are used to light a “halt” in-
dicator.

The Multiplexed Bus

To free enough pins in the
standard 40-pin DIP package to
provide for all these 8085
features, the eight-bit data and
16-bit address buses of the 8080
and Z-80 have been combined in-
to a multiplexed eight-bit data-
and-low-address bus and a non-
multiplexed eight-bit high-
address bus. An additional
strobe comes out of the ’85 on
pin 30 to separate the data from
the low-address bits on the
multiplexed bus.

In any system — large or
small— it is necessary to output
a stable address before data

+ 5V

Fig. 1. CPU section of a maximum-size microcomputer based on the 8085. The four 20-pin ICs shown on
the right can provide all the address, data and control lines for systems with up to 64K bytes of memory
and 256 I/O ports. Five vectored interrupts are available without the need for external interrupt con-
trollers. All 40 pins on the 8085 package are used in the configuration.

Microcomputing, October 1980 107

1-6 MHz
-r CRYSTAL

♦5V

< .

:• iok

vcc

CLK

RESET OUT
REAOY
AIO
A9

^ 25/iF

TRAP
RST T 5
RST 6 3
RST 5 3
INTR

T

8085

CPU

A07
AD6
AD 5
AD4
AD3
AO 2
ADI
ADO
ALE
10/M

CE VCC IOR

CLK PAO

RESET PA I

READY PA2

AIO PA 3

A9 0755 PA4

A8 2K PA 5

A07 EPROM/ pA6

AD6

10

AD5

ADA

AD3

AD2

ADI

ADO

ALE

10/M

RD

IOW

CE VOO VSS

U4

PROGRAMMABLE

INPUT/OUTPUT

LINES

Fig. 2. A minimum-size controller based on the 8085 microprocessor.
The 8755 is a 2K byte ultraviolet erasable EPROM combined with two
8-bit input-output ports. For “ RAM-less ” applications, where CPU
registers can supply sufficient read-write storage, the components
shown here can comprise a complete controller operating from a
single + 5 V dc supply.

Device

Package

Features

8155

8156

40-pin DIP

The 8155 and 8156 both provide 256 bytes of RAM,
a 14-bit counter/timer, two eight-bit I/O ports and
a six-bit I/O port. These two devices have comple-
mentary chip enable levels, permitting them to be
used together without external address decoding.

8185

18-pin DIP

A IK byte static RAM in a small package, made
possible by bus multiplexing.

8355

40-pin DIP

2K bytes of mask-programmable ROM; two eight-
bit I/O ports.

8755

40-pin DIP

2K bytes of ultraviolet erasable EPROM; two eight-
bit I/O ports. Pin compatible with the 8355, it
permits program development for later inclusion in
the 8355.

Table 1. MCS-85 system single +5V supply peripherals with the

multiplexed data/address bus.

transfer can occur. This is true
for read or write, memory or I/O
operations. For this reason,
there is no loss of time resulting
from multiplexing address and
data. The 16-bit address ap-
pears on the address bus (bits
A8 through A15) and address-
data bus (bits ADO through AD7)
along with an address latch
enable (ALE) strobe used to save
the low-order address bits in ex-
ternal hardware. With the ad-
dress stable, and following the
ALE, the AD bits are used as a
bidirectional data bus, just as in
the 8080 and Z-80.

In minimum systems, a
number of multiplexed-bus
peripheral circuits use the ALE
signal to differentiate between
address and data information
sequentially applied to the same
eight pins. Fig. 2 shows that no
external components are re-
quired to implement such a
minimum system. Compatible
peripheral chips can provide
RAM, ROM or EPROM memory,
combined with counters, timers
and I/O lines (see Table 1).

In larger systems— with more
RAM and ROM memory— the
address and data buses from
the CPU have to be buffered in
any case, so there is no increase
in package count between the
8085 bus and that of the 8080 or
Z-80. The only difference is that
an octal latch (8212 or 74LS273)
replaces a bus buffer, and at lit-
tle or no increase in cost. Fig. 1

shows the nucleus of a large
system, with fully buffered ad-
dress, data and control lines.

The NSC800

The 8080 instruction set has
become the industry standard. If
you examine programs written
for the Z-80, you will see that too
many programmers use few, if
any, of the Z’s additional in-
structions. Many reasons exist
for this deplorable situation: no
Z-80 assembler available on old-
er development systems, the dif-
ficulty of converting to a new
set of mnemonics or just plain
lethargy.

If you aren’t using the extra in-
structions anyway, the recent
price reductions and more
widespread availability of the
8085 and compatible periph-
erals have made the 8085 more
attractive. Designing hardware
based on the ’85 is a snap, and
managers just love the low
package counts that result, but
if only it contained the Z-80 op
codes!

Sprouting a new trunk on the
8080 family tree, National Semi-
conductor has combined the
super pin-out of the 8085 with
Z-80 instructions. Now you can
have the ’85 pin-out, with its
five instant hardware interrupts,
serial I/O and single component
clock generator, and the Z-80 in-
struction set executing at one
million instructions a second,
run by flashlight batteries! ■

RESOLUTION

005"

DIGITAL

PLOTTER

PRINTERS

COLOR GRAPHICS FROM
SMALL PLOTTERS WITH
DIG IDEAS.

But draw the line on price. That’s practical!

232 SERIAL IN

FROM $310. SOFTWARE FURNISHED

WRITE FOR DETAILS TO
X- Y ENTERPRISES P.O. BOX 796
HUNTSVILLE. ALA. 35804 ^337

UPDATE:
<TRS-80 * & ISS!

INCREASE YOUR TRS-80*
CAPABILITIES

WITH OUR QUALITY PRODUCTS

• COLOR GRAPHICS BOARDS:

Model C-1000 $129 95

Model C-2000. $189 95

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• lower case BOARD $41 95

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ADD S3 00 POSTAGE And HANDLING

Dealer Inquiries Welcome!

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= =§y§lbeim§ Jlinp., — — .

1011 WEST BROADWAY VfSA'

MINNEAPOLIS, MN., 55411

(612) 522-6631 “Trademark of Tandy Corp-

108 Microcomputing, October 1980

PAGE FOR PAGE . . .
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MICROCOMPUTING
OFFERS YOU MORE.

Go ahead, count them . . . Kilobaud Microcomputing has more pages of articles
each month than any other computer magazine. Articles that keep you in touch with
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By reading the articles in Kilobaud Microcomputing you’ll get to understand how
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be best for you, how the various programming languages work, what is new in both
equipment and programs . . . and you’ll learn how to write your own programs.
You’ll find hundreds of dollars of computer programs listed in the magazine . . . pro-
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Subscribe to Kilobaud Microcomputing today . . . with more articles (and better arti-
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Microcomputing, October 1980 109

ivmiii srmii/Fiim

bursts nssmislnn [taidaMn

Readers will recall that last
month in this newsletter we an-
nounced the advent of the Exa-
tron Stringy/Floppy for the
PET. Did YOU feel left out?
Weil. . . .

THE APPLE ES/F
IS HERE!!

The Exatron Stringy/ Floppy -
ES/F for short-is a mass storage
subsystem for microcomputers.
It does what an audio cassette
machine does, but with very
high reliability, and high speed.
It does what a floppy disk sub-
system does, a little slower and
is half the cost. It’s a way to
store all your programs, both
BASIC and machine language,
quickly and surely, ready to load
back into memory in a few
seconds when needed. It has its
own operating system, and is a
superior way to handle the stor-
age for your word processing
tasks, software systems develop-
ment projects, and data files for
data processing routines. Seeing
one of these remarkable micro-
peripherals in action will con-
vince you!

WHERE DID IT COME FROM?

The Apple ES/F has a good
pedigree. The Stringy/ Floppy
was introduced at the 2d West
Coast Computer Faire in Feb-
ruary 1978, for the S-100 bus.
Later that year the ES/F for the
SS-50 bus and the 6800 was per-
fected. In May 1979 the first
ES/F for the TRS-80 was in-
troduced at the 4 th West Coast
Computer Faire. Early in 1980
the ES/F with the RS-232 inter-
face was on the market, followed
by one for the PET. Exatron has
been manufacturing handlers and
test equipment for the elec-
tronics industry for many years,
and brings those high standards
to the development and manu-
facture of the Stringy/Floppy.

WHAT DOES IT CONSIST OF?

The Apple ES/F consists of
everything you need: a Drive
Module, a Controller Card to in-
sert in one of the Apple card

Secretary , Fred Waters
slots, a flat ribbon cable connect-
ing the two, and miniature tape
cartridges called wafers. The
Drive Module is housed in an
attractive case to match your
Apple; inside are the drive motor,
the read and write tape heads,
the read/write electronics, and
operating controls for tape po-
sitioning and write protection.
On the front face are the drive
slot where you insert the wafer
for SAVE or LOAD, and two
indicator LEDs. The Controller
Card contains the interface elec-
tronics for the Apple, and a
ROM holding a bootstrap loader
to load in the programs which
make up the Stringy Operating
System-SOS for short.

The Stringy/Floppy is phys-
ically integrated into your Apple
II or Apple II Plus simply by in-
serting the ES/F Card into one
of the card slots. It uses very little
power, all of which is provided
by the Apple bus.

The wafers are small tape
cartridges 68mm x 4 0mm -two
thirds the size of a business card
-and 4.5mm thick. Inside is a
continuous loop of digital qual-
ity tape in varying lengths from
5 feet to 75 feet providing dif-
ferent storage capacities. The
wafer case is entirely enclosed
except for a small slot where
the drive capstan fits and another
for contact with the tape head,
for protection from handling and
foreign particles. With each ES/F
comes one wafer with SOS on
tape, and a number of blank
wafers for you to SAVE pro-
grams on.

The initial configuration has
one Controller Card and one
Drive Module. However the Con-
troller will operate two Drives—
all you do is connect the second
unit. You can add as many Con-
troller Cards as you have slots
for-each one will allow two
more drives.

WHAT WILL IT DO?

When the SOS (Stringy Op-
erating System) is loaded into
Apple memory by the bootstrap
loader in ROM, it integrates it-
self into your BASIC-whether
Integer or Applesoft-and re-
turns you to the BASIC prompt.

If you have any questions about these products, about Exatron or
about ES/FOA call the Hot Line. Address letters to ES/FOA, 181
Commercial Avenue, Sunnyvale, CA 94086.

Stringy/Floppy is a trademark of Exatron Corporation.

You now have everything you
had before in the way of BASIC
commands, statements, and op-
eration, with the addition of the
complete SOS and all the ES/F
commands. The ES/F commands
will SAVE, LOAD, and RUN
(load with autostart) programs
in BASIC (either one or both);
they will SAVE, LOAD, and
RUN programs or data in binary
(machine code); they will select
either BASIC as desired when
you have both in your Apple;
and one command, CATALOG,
displays a complete directory of
the contents of a wafer.

The directory shows the posi-
tion of each file on tape, the
file type (Applesoft, Integer, or
Binary), the starting address,
the length of the file in bytes,
and the file name. The SAVE
commands include optional pa-
rameters for slot number, drive
number, file position, and VERI-
FY. With VERIFY, SOS will
SAVE the file with the nec-
essary parameters, and then run
the tape around the continuous
loop and compare the file just
SAVEd against memory. When
you SAVE your programs this
way, you KNOW you have them
right on the wafer! File names
can be up to 30 alphanumeric
characters-you don’t have to
correlate numbers and names
separately.

HOW WELL DOES IT DO IT?

Here are some of the features,
and what they will do for you.
You’re already familiar with the
seemingly interminable delays in
loading a program from audio
cassette. The Apple ES/F saves
and loads program material at
16,000 baud, or roughly 2K
bytes per second. Tape speed is
10 inches per second. This means
that you can save 10K bytes
on the 5-foot wafer, and the
ES/F will save and load this
much material in six seconds!

What about reliability? Well,
once you have certified a new
wafer, it has a life expectancy
of at least 10,000 passes. The
error rate is so low that you may
use the ES/F for weeks without
ever running into a read or write
error. There is a write-protect

HOT LINE

WITHIN CALIFORNIA

feature built into the ES/F to
help you avoid operating errors.

Since the ES/F was designed
from the ground up to digital
standards for use with industrial
quality equipment, you are not
handcuffed to using audio equip-
ment, audio materials, or audio
standards for your Apple. There
are no buttons, knobs, or switch-
es to adjust when you save or
load programs. The operations
are all controlled by the soft-
ware, and are highly reliable.

WHY DO YOU NEED TWO
DISKS?

Did you read Stutsman’s article
on page 84 of Microcomputing
for August? It’s titled “Why Do
You Need Two Disks?” Jim
Stutsman may never have tried
out a Stringy/Floppy, but he
puts forth some of the best
arguments I’ve ever heard on why
YOU need an ES/F. He wonders
why (to paraphrase somewhat)
we’d want to buy solutions to
problems we’ve never had, and
probably never will have. If
you’re not satisfied with audio
cassette standards for your high-
quality computer, but don’t have
the money to spend on one or
two disks, check out the Exatron
Stringy/ Floppy. It meets Stuts-
man’s suggested minimum stand-
ards for a good DOS, and will
speak for itself when you try it
out.

PRICES AND ORDERING

The ES/F is assembled and tested
at the factory, with a 30-day
money back guarantee and a one
year full warranty. For fastest
delivery, phone in your credit
card or COD order using the toll-
free line below.

Base price for the TRS-80
ES/F, $249.50 (ask about the
Starter Kit); for the S-100 ES/F,
$289.50; Apple and PET with
single drive is $299.50, dual
drive is $4^9.50

Info packets at no charge;
users manuals for the TRS-80
ES/F are available for $3.00 for
shipping.

Handling is extra.

800 - 538-8559

408 - 737-7111

* advertisement *

FINALLY

AN ALTERNATIVE TO DISKS

THE EXATRON STRINGY FLOPPY

(MASS STORAGE SUBSYSTEM)

TO REQUEST AN INFORMATION PACKAGE
EXATRON, INC. ■ 181 COMMERCIAL STREET ■ SUNNYVALE. CA 94086

OEM

exatron

E TODAY

800 - 538-8559

S-100

RS-232

STD-BUS

LOW COST - RELIABILITY - SPEED

INFORMATION PACKAGES
APPLE
PET
TRS-80
OSI

KIM/SYM/AIM

Area Estimation

It's simply a matter of BASIC geometry .

100 REM MAIN PROGRAM — MUST SPECIFY X AND Y COORDINATES PRIOR TO
110 REM EACH CALL. SETTING FLAG F TO 1 RESETS ROUTINE. STOP INPUT BY
120 REM ENTERING NEGATIVE NUMBERS.

130 F=1

140 PRINT "ENTER THE X AND Y COORDINATES ? ";

150 INPUT X,Y

160 IF X<0 OR Y<0 THEN 190

170 GOSUB 500

180 GO TO 150

190 PRINT "TOE AREA IS ";A
200 END
450 REM

460 REM AREA COMPUTATION SUBROUTINE. XI, Y1 SAVE COORDINATES FOR
470 REM NEXT CALL. A IS AREA. B KEEPS SUBTOTAL. F=1 INDICATES TO
480 REM PROCESS ON FIRST CALL. XO, YO SAVE FIRST POINT COORDINATES.
490 REM F=0 RESETS FLAG.

500 IF F=1 THEN 570
510 A=B+X1 *Y-Y 1*X
520 X1=X
530 Y1=Y
540 B=A

550 A=- ( A+X*Y 0-X0*Y ) *0 . 5
560 RETURN
570 X1=X

580 Y1=Y
590 B=0
600 A=0
610 X0=X
620 Y0=Y
630 F=0
640 RETURN

Program A (for a Tektronix 4051).

RUN

ENTER THE X AND Y COORDINATES ? 0 0
2 3
0 4

2.6666 4
4 6

5.3333 4
8 4
6 3
8 0
4 2
-1 -1

THE AREA IS 18.6667

Program A sample run (corresponds to
Fig • 1).

Fig. 1. Example of irregular figure whose
area is estimated by Program A.

Arnold W. Bragg
409 Cedar Hill Lane
Raleigh, NC 27609

n educated guess is often the best we
can do when calculating the area of
complex and irregular geometric shapes.
While the area can sometimes be estimated
by subdividing the figure into a mosaic of
rectangles, triangles and circles, this

piecemeal technique is unsuitable for com-
plex figures, and often lacks the precision
required in sophisticated applications. A
more precise computational tool is needed,
one that will suit both the engineer and the
hobbyist.

The area estimation software described
here can calculate areas under function
curves and areas of machine-generated
figures, map sections, floor plans, survey
plats and aerial photograph segments.
Students can use the software routine to
check geometry and integral calculus com-
putations, or compute the surface area of
butterfly wings and flower petals.

The software has been designed with
three criteria in mind. First, the area com-
putation algorithm must be a distinct
module that does not require modification
as the application changes. Second, the
algorithm must be designed to run on
machines having 4K of memory. Finally, the
resulting area estimate must be mathemati-
cally correct. Compliance with these fea-
tures guarantees the algorithm's suitability
over a wide spectrum of users, machines
and applications.

To estimate the area of any irregular
shape we need only furnish the algorithm
with the x- and y- coordinates of an arbitrary
number of points lying on the figure’s
perimeter. The more data points we furnish,
the better our estimate becomes. Because
we are approximating curved segments
with tiny straight line segments, the density
of our data points should reflect the cur-
vature of the perimeter.

At this stage we impose the algorithm’s
only restriction: We must traverse the figure
in a clockwise manner. This guarantees
that the area of the figure has the correct
sign. The restriction assures us of
mathematical correctness, which will be
important later when we consider areas
above and below an axis baseline.

112 Microcomputing, October 1980

RUN

ENTER INITIAL X VALUE ? 0
ENTER FINAL X VALUE ? 2
ENTER INCREMENT OF X ? 1
THE AREA IS 4

RUN

ENTER INITIAL X VALUE ? 0
ENTER FINAL X VALUE ? 2
ENTER INCREMENT OF X ? 0.1
THE AREA IS 3.34

RUN

ENTER INITIAL X VALUE ? 0
ENTER FINAL X VALUE ? 2
ENTER INCREMENT OF X ? 0.01
THE AREA IS 3.3334

RUN

ENTER INITIAL X VALUE ? 0
ENTER FINAL X VALUE ? 2
ENTER INCREMENT OF X ? 0.001
THE AREA IS 3.33333399999

Program B sample run 1 (corresponds to
Fig. 2).

Fig. 2. Example of bounded area estimated
by sample run 1 of Program B.

The Algorithm

Because the area estimation algorithm is
suited to different applications, it has been
incorporated into a subroutine that can be
appended to a user’s BASIC program as
needed. The subroutine requires only three
values at each call: the data point’s
x-coordinate, its y-coordinate and a status
variable, or flag, whose value must be set by
the user prior to the first subroutine call.

The subroutine computes the area of a
polygon whose vertices (corners) are the
data points entered so far. For example,
after three subroutine calls, the algorithm
has calculated the area of the triangle
whose vertices are the three data points
supplied with each call. The area is zero
after the first and second calls because
polygons with one or two vertices enclose
no area.

Program A illustrates how to calculate
the area of the flattened star of Fig. 1. Each
vertex (corner) of the star represents a data

100 REM MAIN PROGRAM — FUNCTION PROCESSING — LINE 240 DEFINES FUNCTION
110 REM AND I, J ARE BOUNDS ON X, K IS X INCREMENT SIZE, X AND Y ARE
120 REM CALCULATED FRIOR TO EACH CALL.

130 PRINT "ENTER INITIAL X VALUE ?

140 IN PITT I

150 PRINT "ENTER FINAL X VALUE ?

160 INPUT J

180 PRINT "ENTER INCREMENT OF X ? "?

190 INPUT K
200 F=1
210 X=I
220 Y=0
230 GOSUB 500
240 Y=2*X*X-3*X+2
250 GOSUB 500
260 X=X4K

270 IF X<=J THEN 240

280 X=J

290 Y=0

300 GOSUB 500

310 PRINT "TOE AREA IS ";A
320 END
450 REM

460 REM AREA COMPUTATION SUBROUTINE. XI, Y1 SAVE COORDINATES FOR
470 REM NEXT CALL. A IS AREA. B KEEPS SUBTOTAL. F=1 INDICATES TO
480 REM PROCESS ON FIRST CALL. X0, Y0 SAVE FIRST POINT COORDINATES.

490 REM F=0 RESETS FLAG.
500 IF F=1 THEN 570
510 A=B+X1 *Y-Y 1 *X
520 X1=X
530 Y1=Y
540 B=A

550 A=- ( A+X*Y 0-X0*Y ) *0 . 5

560 RETURN

570 X1=X

580 Y1=Y

590 B=0

600 A=0

610 X0=X

620 Y0=Y

630 F=0

640 RETURN

Program B.

point supplied to the subroutine (lines
450-640) by an INPUT statement in the main
program (lines 100-200). Our sign restric-
tion forces us to traverse the star in a
clockwise manner. Otherwise the area
would be of the correct magnitude but
would have a negative sign. We halt the
routine by entering a negative X or Y value.

Variable F is the status flag, which is set
to 1 in line 130 to indicate a first call. F is
tested in line 500 for first call and reset in
line 630 of the subroutine to zero for subse-
quent calls.

Variables X and Y represent the x- and
y-coordinates of the most recently entered
data point, and are supplied by the main
program before each call.

Variables X0 and Y0 save the coordinates
of the first data point for later processing.
These values essentially allow us to “close
the box.”

Variables XI and Y1 are the coordinates
of the next-to-last data point entered.
Variable B keeps a running subtotal of the
area, and variable A is the area of the
polygon defined by the data points.

RUN

ENTER INITIAL X VALUE ? 2
ENTER FINAL X VALUE ? 8
ENTER INCREMENT OF X ? 1
THE AREA IS -41.75

RUN

ENTER INITIAL X VALUE ? 2
ENTER FINAL X VALUE ? 8
ENTER INCREMENT OF X ? 0.1
THE AREA IS -41.9975

RUN

ENTER INITIAL X VALUE ? 2
ENTER FINAL X VALUE ? 8
ENTER INCREMENT OF X ? 0.01
THE AREA IS -41.999975

RUN

ENTER INITIAL X VALUE ? 2
ENTER FINAL X VALUE ? 8
ENTER INCREMENT OF X ? 0.001
THE AREA IS -41.9999997499

Program B sample run 2 (corresponds to
Fig. 3).

Fig. 3. Example of negative bounded area
estimated by sample run 2 of Program B.

Microcomputing , October 1980 113

Calculating the Areas under
Function Curves

Let’s consider several examples. If we
wish to compute the area under a function
curve between two distinct points (Fig. 2)
and we don’t know the equation of the func-
tion we are dealing with, we use the ap-
proach outlined in Program A. We plot the
function, estimate the x- and y-coordinates
of a reasonable number of data points and
supply these in sequence to the subroutine.

Generally, the more points estimated, the
better our area estimate becomes.

If we know the equation of the function,
we need only a simple routine to specify the
beginning and ending X values and to in-
crementally calculate and pass x- and
y-coordinates to the subroutine. Consider
the equation Y = 2X 2 - 3X + 2 between X = 0
and X = 2 (Fig. 2). Program B defines the
main procedure and illustrates how the
area estimate approaches the true area as

the magnitude of the X increment is
decreased. We must specify the starting
point on the X axis (X = 0, Y = 0) and call the
subroutine. Our program increases X by
some increment, calculates the corre-
sponding Y value, then passes these new co-
ordinates to the subroutine. When X has
been incremented to 2 (the right bound), we
drop to the x-axis and define the last point
(X = 2, Y = 0). We conclude by calling the
subroutine for the last time and displaying
the estimated area.

Lines 130-190 of Program B request the
left and right bounds and the X increment.
Line 240 defines the functional equation
and line 270 tests for the right bound of X.
Line 310 displays the resulting area
estimate.

If a segment of the function lies below
the x-axis, then the area estimate of that
segment has a negative value. Consider the
equation Y = 0.25X 2 -X-9 between X = 2
and X = 8 (Fig. 3). Changing line 240 of Pro-
gram B to Y = .25*X*X - X - 9 produces the
estimates of Sample run 2. If we processed
the function of Fig. 3 between X = 2 and
X= 12.955 with a very small increment size,
our estimate would approach zero; the area
of the segment above the X axis is approx-
imately equal to the (negative) area of the
segment below the X axis, and the two
cancel.

Calibrating the Areas of Irregular Figures

Consider the map in Fig. 4. We can
estimate its area by selecting data points
and supplying the coordinates of the sam-
ple points to Program A. But our set of axes
has no grid as in Fig. 1. How can we
estimate the X and Y coordinates? In what
sort of units will our result be?

We obtain the coordinates of the data
points by digitizing the outline of the figure.
The digitization process can be ac-
complished by using a digitizing tablet or
an optical scanner, or by overlaying the
map with a sheet of ruled graphing paper

100 REM MAIN FROGRAM — LINES 140-200 COMPRISE CALIBRATION MODULE, LINES
110 REM 210-290 COMPUTE AREA OF SEGMENT, ADJUSTMENT FOR CALIBRATION
120 REM FACTOR IS MADE IN LINE 270. R IS CALIBRATION UNIT AREA.

130 F=1

140 PRINT "ENTER THE X AND Y COORDINATES FOR CALIBRATION FIGURE ?

150 INPUT X, Y

160 IF X<0 OR Y<0 THEN 190

170 GOSUB 500

180 GO TO 150

190 R=A

200 PRINT "THE AREA OF THE CALIBRATION FIGURE IS ";A
210 F=1

220 PRINT "ENTER THE X AND Y COORDINATES ? ";

230 INPUT X, Y

240 IF X<0 OR Y<0 THEN 270

250 GOSUB 500

260 GO TO 230

270 A=A/R

280 PRINT "THE CALIBRATED AREA IS ";A; "UNITS"

290 END

470 REM NEXT CALL. A IS AREA. B KEEPS SUBTOTAL. F=1 INDICATES TO
480 REM PROCESS ON FIRST CALL. X0, Y0 SAVE FIRST POINT COORDINATES.

490 REM F=0 RESETS FLAG.

500 IF F=1 THEN 570
510 A=B+X1 *Y-Y 1*X
520 X1=X
530 Y1=Y
540 B=A

550 A=- (A+X*YO-X0*Y) *0. 5

560 RETURN

570 Xi=X

580 Y1=Y

590 B=0

600 A=0

610 X0=X

620 Y0=Y

630 F=0

640 RETURN

Program C.

Fig. 4. Example of calibrated area
estimated by Program C.

RUN

ENTER THE X AND Y COORDINATES FOR CALIBRATION FIGURE 7 0 0
0 5
5 5
5 0
-1 -1

THE AREA OF THE CALIBRATION FIGURE IS 25

ENTER THE X AND Y COORDINATES ? 5 10
4 11
3.5 12

10 6
9 6.5
6 8.7
-1 -1

THE CALIBRATED AREA IS 8.25017 UNITS

Program C sample run (corresponds to Fig. 4).

114 Microcomputing, October 1980

and reading the coordinates directly. Then,
by defining a unit of known area (for exam-
ple, box A of Fig. 4 = 1 square mile) and
dividing our final result by this calibration
factor, we guarantee that our results are in-
dependent of the coordinate scaling factor
or grid size chosen, and are also expressed
in terms of the units measured (in this case
square miles). Program C illustrates how
the calibration program estimates the area
of the SUBURBIA subsector of Fig. 4.
Notice that the calibration module uses the
area subroutine to calculate correction
factor R (line 130-200).

As indicated in Programs A, B and C, the
area estimation subroutine is suited to
several different applications, and requires
only a small amount of memory for im-
plementation. Applications differ only in
the method by which data points are
selected. The selection methods alter the
calling routine; the subroutine never needs
to be modified.

Program A is used when a convenient
grid scale exists and data points with non-
negative coordinates can be read directly
from the scale, traversing clockwise. Pro-
gram B is suited for numerical integration
applications between specific bounds.
Area segments below the x-axis display the
correct sign. Program C is useful when the
area estimate must be expressed in stan-
dard or non-standard units such as square
inches or acres rather than in terms of the
unit imposed by the grid scale.

In each case, our accuracy depends only
on the number of sample data points we
select to reasonably represent the figure
and the precision with which the x- and
y-coordinates of these data points are
estimated. ■

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tS Reader Service index— page 241

— r J

Microcomputing, October 1980 115

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116

Microcomputing, October 1980

Thoughts on the

SWTP Computer System

The author takes a closer look at the 6809 and its Motorola BASIC, discusses
multiprogramming and presents two interrupt-driven printer programs.

Peter A. Stark

PO Box 209

Mt. Kisco, NY 10549

S ince my comments on the 6809 ap-
peared in the January issue, several
readers have chided me for urging caution.
Perhaps I wasn’t clear enough in my com-
ments. Here’s what I intended to say.

I’m impressed by the 6809. It’s about the
best microprocessor around. The fact that
so many other manufacturers are planning
computers using it— including the TRS-80
Color Computer— is testimony to the fact
that others think it’s great too.

But as of now, its capabilities are not be-
ing utilized. 6809 software as of last
January was simply reassembled 6800
code. While this software runs faster on the
6809, it doesn’t take full advantage of the
6809’s potential. Thus, rushing to convert to
the 6809 just didn’t make sense, especially
since it wasn’t definite whether the ap-
proaches of several different companies
active in the software and hardware areas
would be compatible. Hence, my caution
and somewhat negative article.

In the meantime, there has been frantic
activity to develop the software to take ad-
vantage of the 6809’s capabilities.
Moreover, what started out as
bedlam — with each manufacturer heading
off in a different direction — is now being
coordinated, with most of the SS-50 bus
manufacterers keeping in contact and ex-
changing hardware and software to make
sure their products are compatible. That is
a welcome sign.

Motorola’s BASIC-09

One of the most important developments
is a new BASIC from Motorola. As you re-
member, the 6800 received a bad and unde-
served reputation for being slow simply be-
cause the first 6800 BASICS were slow
(though excellent in other respects). It
makes you wonder where the 6800 would be
with respect to the 8080 and Z-80 had
Motorola initially spent the money to de-

velop an excellent BASIC, which they are
now developing for the 6809.

For over a year, Motorola has had a con-
tract with Microware to develop a new
BASIC called BASIC-09. A preliminary ver-
sion was on display at the Gimix booth at
the West Coast Computer Faire in March
and caused quite a stir. I’ve read the
preliminary manual and hope to have a
chance to try it out soon for a more com-
plete report. But the manual is amazing.

BASIC-09, a structured language, bor-
rows some of the better features of Pascal.
Line numbers are optional; the program is
broken up into sections called procedures,
with each having a name. Procedures then
call each other by name. Line numbers, if
used, as well as variables, are local to the
procedure, so other procedures can use the
same line numbers or variables. If you’re in-
to structured programming, then you’ll like
this BASIC; if not, then just ignore pro-
cedures and write the whole program as
one big procedure.

BASIC-09 has five types of vari-
ables— byte, integers (up to 32,767), real
(nine-digit precision using 40-bit floating
point binary), Boolean (true-false) and string
(with string length up to 32,768 characters).
You can define your own data formats by
combining these five data types into larger
data structures.

For BASIC old-timers, BASIC-09 has the
standard GOTO statement; for structured
programming aficionados who don’t like
GOTO, there are also
IF.. .THEN. ..ELSE
REPEAT...UNTIL
WHILE. ..DO

and other structures in Pascal.

BASIC-09 is a semi-compiler like the new
TSC BASIC; that is, as each line is typed in,
it is immediately checked for accuracy and
translated into an internal code that makes
later execution faster. When the program is
listed, it is translated into plain BASIC and
printed in an indented form for easy
reading. BASIC-09 also includes an editor
function that has extensive editing
capabilities, including renumbering and
string replacement. Variable names and

procedure names can be any length, upper
or lowercase.

For debugging, BASIC-09 allows tracing,
which prints out each source line before it is
executed, as well as the values of variables
as they are assigned. At any point, the pro-
gram can be suspended, and the variables
can be read out or changed.

Microware has also developed an
operating system called OS-IX (pronounced
OS-nine). Although OS-IX is available with
BASIC-09, it is also available separately
from Microware. It is essentially a device-
independent operating system that pro-
vides the interface between BASIC-09 or
other languages and the hardware.

BASIC-09 will probably be available in
ROM from Motorola as well as in disk-based
versions directly from Microware.

For those users who want disk-based
BASIC, Microware has signed a contract
with Microsoft and will supply Microsoft
BASIC 5.0, along with OS-IX, on disk. The
advantage of this is that all the business
software that now runs on other versions of
Microsoft BASIC will also run with this
BASIC. Present plans are to make this soft-
ware compatible with both 5 inch and 8 inch
floppy d r sks, as well as several different
disk controllers.

At this point, it is still not definite as to
what hardware will be required for what
software. If you’re happy with your 6800
system, stick with it until some more dust
settles.

Time-Sharing and Multitasking

Most of us use our 6800 systems for just
one job at a time. But the 6800 is versatile
enough that it can execute several func-
tions at one time. All of these require inter-
rupts in one way or another.

The top eight locations in a 6800’s mem-
ory, locations FFF8 through FFFF, contain
four transfer vectors that correspond to the
three interrupt inputs and reset as follows:
FFF8 and FFF9 — IRQ interrupt
FFFA and FFFB — SWI interrupt
FFFC and FFFD — NMI interrupt
FFFE and FFFF - Reset
(Reset is not really an interrupt, but it

U* Reader Service index— page 241

Microcomputing, October 1980 117

behaves in a similar way.)

When the RESET switch is pressed, for
instance, the 6800 stops whatever it is do-
ing, fetches the vector that is stored in loca-
tions FFFE and FFFF in ROM and executes
a jump to the address that the vector points
to. For instance, in SWTBUG or MIKBUG,
locations FFFE and FFFF contain the
number E0D0. Hence, pushing RESET will
force the computer to execute a jump to
location E0D0, which is the beginning of the
monitor.

Interrupts act a little differently. When
one of the two interrupt inputs to the 6800
(either IRQ or NMI) is grounded, or when the
program encounters an SWI instruction, the
6800 also completes its current instruction
and then jumps to wherever the correspond-
ing vector in ROM is pointing. However, be-
fore that jump it stores the contents of its
internal registers in the stack. Later, an RTI
instruction will fetch all of the information
back off the stack and allow the 6800 to
resume running the program that had been
interrupted as though nothing happened.

The three interrupt methods have dif-
ferent uses. The SWI instruction is usually
used for debugging (we have already seen
in this series how it can be used with break-
points and single-stepping). It can also be
used for subroutine calls. For instance,

GMXBUG uses the SWI to return to the
monitor so that a system subroutine can be
executed.

IRQ interrupts are usually used to allow
I/O devices to call for help from the pro-
cessor. An IRQ interrupt request (via a
grounded IRQ pin) will be ignored by the
6800 if the I bit in the condition code register
is a 1, so that important programs can turn
on this bit and prevent IRQ interrupts from
occurring.

This important feature is called masking.
Certain kinds of programs -such as disk
reads and writes, which have critical timing
and would make errors if they were inter-
rupted-can set the I bit and prevent
themselves from being interrupted. Further-
more, once an interrupt occurs, further in-
terrupts are usually masked to prevent
some other problems.

NMI interrupts, on the other hand, are not
controlled by the I bit in the condition code
register; NMI stands for nonmaskable inter-
rupt. When an NMI interrupt request oc-
curs— when the NMI pin on the 6800 is
grounded— an interrupt will occur, regard-
less of what else is going on.

Hence, NMI interrupts are usually re-
served for important events, where the pos-
sible loss of data is not important. A typical
case is a power-fail interrupt, where a sen-

sor in the power supply generates an NMI
interrupt when power fails, with the idea of
giving the 6800 a few milliseconds— until
power supply capacitors discharge,
perhaps — to stop executing a program and
either save data or at least go into a fail-
safe mode before all power goes off.

Thus, for time-sharing or multitasking,
we’re usually concerned with the IRQ inter-
rupt. IRQ interrupt requests can either
come from an I/O device that asks for an in-
terrupt when it needs the CPU or from an ex-
ternal timer that generates interrupts at
fixed intervals.

Why would you want to generate these
timed interrupts? There are several possible
reasons:

1. An interrupt routine could keep count
of these interrupts and use them to keep
track of the time and date, which could then
be stored in some memory locations and
read out by other programs. Such an ap-
proach was described in an article by
Richard Parry in the January 1980 issue of
Kilobaud Microcomputing on page 150.
(Richard’s scheme was a bit indirect: inter-
rupts did not go to the 6800 directly, but
went through a PIA first. But that’s not im-
portant.)

2. A timed interrupt could be used to time
external outputs. For instance, if we wanted

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to output serial five-level code out of one of
the outputs of a PIA at 45 baud, then an in-
terrupt occurring every 1/45 of a second
could be used to time the outputs.

3. When we want to run several programs
in a round-robin fashion, giving each a cer-
tain amount of time, an interrupt timer can
cause the transfer of control from one pro-
gram to the next. This is essentially the idea
behind time-sharing. There are several 6800
products designed for running multiple pro-
grams in this fashion.

Microware’s RT-68

Our discussion of monitors has already
covered some of the features of the RT-68;
let’s look at just its multitasking operation.

With the RT-68, CPU time is allocated to
each of up to 16 programs (called tasks) in a
round-robin fashion, so that these tasks ap-
pear to run concurrently. These tasks may
be independent or may depend on each
other and share data.

RT-68 keeps track of these by maintain-
ing a task status table in locations A050
through A07F. For each of the 16 possible
tasks, the table contains three bytes of in-
formation. The first of these is a TSB, or
task status byte, while the other two con-
tain a TSP, or task stack pointer.

Tasks are started and stopped by inter-

rupts; since each interrupt stores register
contents in the stack, each of the 16 tasks
has to maintain its own stack area to keep
this data separate from all other tasks.
Thus, the task stack pointer in the table
points to the stack used by each task. Keep
In mind that of the 16 possible tasks, only
one task is actually running at any one time;
task stack pointers for the other 15 are con-
stantly kept in the table.

Tasks can have one of three states:

1. Currently executing.

2. Active, that is, not currently running, but
ready to run as soon as their turn comes.

3. Inactive, that is, not currently running and
also not ready to run.

Although RT-68 can handle up to 16
tasks, in most cases a much smaller
number of tasks will be active. There could,
for instance, be just two active tasks and 14
inactive ones.

The task status byte is divided into three
sections:

1. Bit 7 indicates whether the task is active
(1) or inactive (0).

2. Bits 6 through 3 indicate how long that
task is to run before being stopped and con-
trol turned over to another task. This time is
measured in interrupts received from an in-
terrupt timer; each interrupt is called a tick,
and a task may be assigned from one to 15

ticks.

3. Bits 2 through 0 indicate a task’s priority.
Each task can be assigned a priority from 0
to 7. Higher-priority tasks get preference
over low-priority tasks; in fact, a low-priority
task will not run at all as long as there are
active higher-priority tasks. There is also a
system priority that RT-68 keeps for itself;
tasks having a lower priority also don’t get a
chance to run.

RT-68 uses an external clock timer, which
generates an interrupt at a fixed interval,
such as every 1/60 or 1/100 second. This is
coupled to a PIA on port 1, and through that
to the NMI line. Thus, the clock generates
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Normally, NMI interrupt requests cannot
be masked, but RT-68 channels them
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i/ 0 Reader Service index— page 241

Microcomputing, October 1980 119

Joyce, 4603 Lyceum Drive, San Antonio, TX
78229. His scheme also uses a task status
table and some similar ideas.

If you have access to old copies of Elec-
tronic Design magazine, a short note by
David Johnson in the February 15, 1978,
issue describes a simple approach to do the
same thing. In this case, switching back
and forth between tasks is initiated by each
task periodically suspending itself by call-
ing the monitor. This approach is simpler
but has the disadvantage that a program
that develops a bug may not release con-
trol.

SWTP Multi-User Board

The approaches I’ve discussed so far are
for running a number of completely sepa-
rate programs; the multi-user board (MUB),
on the other hand, is set up for running one
program with several users. It’s intended to
allow up to four users to run programs in
either the BASIC or Pilot language. Either
way there is only one BASIC or Pilot inter-
preter in memory, and the four users take
turns using it to interpret their own user pro-
grams.

The MUB board occupies memory ad-
dresses 0000 through 0FFF, or the lowest
4K. Thus, only addresses from 1000 and up
are available for user RAM. SWTP states
that the remaining memory from 1000 to
7FFF must be built up out of 4K and 8K
boards and that the 32K memory board can-
not be used with the MUB. This is not so, as
we shall see later.

In any case, the MUB uses up addresses
from 0000 through 0FFF, or 4K. On the
board are four 2114 static RAMs, which pro-
vide 2K bytes of memory, which is split up
into four 512-byte sections, one section for
each user. As in a typical timesharing
system, each user gets a small slice of time,
typically about five milliseconds, during
which his program runs and the other users’
programs are dormant. During this time, his
512 bytes occupy addresses 0000 through
01 FF, while the other three 512-byte
memories are disconnected.

The MUB has a page register at address
0C00 that selects which of the four 512-byte
memories is enabled at any one time. The
variables, stack and various constants for
each user are stored in these 512 bytes and
swapped in and out by hardware when a dif-
ferent number is written into this page reg-
ister to select a different user.

An interrupt timer on the board generates
an I RQ interrupt about 200 times per second
(about five milliseconds apart), so no exter-
nal timer board is required. These interrupts
are generated by a 555 timer, which is dis-
abled when the system is first started but
starts working when a read from location
0800 is executed. Once the clock starts, it
continues running until power is turned off

120 Microcomputing, October 1980

or the reset button is pressed.

The hardware of this board is fairly sim-
ple; it’s the software that makes the whole
operation useful. Normally supplied with
the MUB is a 4K Micro BASIC Plus, which
allows up to four users at the same time.
This is an integer BASIC without strings
that appears similar to the Micro BASIC of-
fered by TSC. In fact, the multi-user board
and multi-user BASIC first appeared in
some TSC ads a few years ago.

Also available are 8K cassette and disk-
based BASICS from SWTP. Using the infor-
mation in the fifth installment of this series
(September 1979), you could modify SWTP
8K BASIC, version 2.0, to work in this mode
too.

Of special interest to teachers, though,
may be the multi-user Pilot also available
from SWTP and Micropi. Pilot is a pro-
grammed instruction language specially
set up for easy programming of question-
and-answer-type programs.

Basically, Pilot commands consist of one
or two letters followed by a colon (T: or M:),
followed, in turn, by some text, for example:

T: What’s your name?

A:

M: Pete, Peter
YT: I like that name.

NT: Too bad

This program says to type (T:) the ques-
tion, “What’s your name?” wait for an
answer (A:) and match that answer (M:)
against either Pete or Peter. If it matches
(YT: means type if yes), print one message;
if it does not match (NT: means type if no),
print another.

Full Pilot allows branching and computa-
tion, but the convenient feature is that it
also will allow partial matches of answers
or even allow alternative answers. For ex-
ample, it will accept an answer even if it is
misspelled or will accept a numeric answer
to a problem even if it is off by a slight
amount. Though BASIC could also be used
for this type of programming, it takes a lot
of work in BASIC to allow for alternative or
partial answers.

MUB Modifications

Since the multi-user board occupies the
lower 4K of memory but only has 512 bytes
of actual memory accessible at any one
time, when it is plugged in, the system will
not run any other programs that require the
lower 4K.

Moreover, SWTP states that the MUB
board cannot be used with the 16K or 32K
dynamic memory board. Thus, to get a full
28K of memory (from 1000 to 7FFF) you
need three 8K boards and a 4K board. When
you unplug the MUB board to fun normal
programs, you then need one more memory
board to supply the lower 4K. Thus, to use
the system you need five memory boards, a
lot of power and almost $1000 (at list price).

Fig. 1. Changes to multi-user board.

With a simple modification, the MUB will
work just fine with the 32K memory board.
Moreover, this modification includes a
switch to enable or disable the MUB, so that
the system can be used for standard single-
user programs without having to plug and
unplug boards. As with some other informa-
tion in previous installments, this modifica-
tion comes from a knowledgeable SWTP
dealer, Lehigh Computer Works, 1132-2
Tilghman Street, Allentown, PA 18102. Tom
Quay of Lehigh has tried this one out and it
works well. I’ll only outline the mod here;
complete details can be obtained from
Lehigh.

The modification simply disables the 32K
memory board whenever the MUB is ad-
dressed. The only specific requirement is
that the memory board contain the full 32K
of memory; this is really of no consequence
because for multi-user applications you’d
probably want this much memory anyway.
The only parts required for the modification
are some wire, an SPDT switch and a 2.2k
resistor.

The switch is optional, but it does allow
the MUB to be switched out, so that the full
32 K of memory becomes usable for normal
program use. This modification also uses
the UD1 line on the motherboard; if your
system is already using this line for some
other purpose, then you’ll have to find some
other way to get a signal from the MUB to
the memory board (such as a direct jumper).

Fig. 1 shows the changes required on the
MUB board. The connection from IC20, pin
10, to the rest of the board must be broken
by cutting a printed circuit land or simply by
bending pin 10 up and out of its socket, if an
1C socket is used. The SPDT switch should
be mounted on the upper left corner of the
board and connected as shown in Fig. 1.
IC22 has an unused inverter, which feeds
the UD1 line on the bus. This signal goes
low whenever the MUB is addressed.

Fig. 2 shows the changes to the 32K
memory board. Jumpers El and E2 should
be removed and a 2.2k resistor connected
instead of E2. This would therefore per-
manently enable the board for the full 32K
of memory from 0000 to 7FFF. But a wire
from UD1 up to pin 2 of U42 as shown

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v* Reader Service index— page 241

Microcomputing, October 1980 121

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IT

U 42^ 0 —

Fig. 2. Changes to 32K memory board.

disables the memory board whenever the
MUB is addressed and sends out a low
pulse on the UD1 line.

When the system is not being used with
the multi-user software, the switch should
be off. To run multi-user BASIC or Pilot, turn
the switch on. The MUB can stay plugged in
all the time.

Another Way

If you are interested in multi-program-
ming, keep in mind a comment I made
several months ago while discussing ex-
pansion of the SWTP 32 K board to 64K. If
the board is configured as two separate 32K
sections, switched by a bit coming from a
PIA, then you can do what the MUB does,
but on a larger scale. Instead of just switch-
ing 512 bytes in and out, you can switch 32K
and provide full memory for each of two
users. In one 32K segment, one user could
do an assembly or run BASIC, while the
other could do something completely differ-
ent in his 32 K.

Printer Interrupts

One down-to-earth application of inter-
rupts is to drive a printer. This is only prac-
tical if you keep a memory. buffer filled with
characters to be printed, while an interrupt
routine empties it at the printer’s own pace.
In this way, the program can run ahead of
the printer and pause only when the buffer
becomes filled up.

In many programs, especially in BASIC,
where the printer runs in bursts, this may
speed up overall running time by as much
as a factor of 2, because the printer can now
run continuously instead of starting and
stopping. The same is true of the program
that drives it.

Applied Microcomputer Systems (Box 68,
Silver Lake, NH 03875) has been offering an
interrupt-driven parallel printer driver for
some time. It is intended primarily for the
SWTP PR-40 printer.

However, many of the newer printers,
such as the Anadex, have a built-in buffer of
1 K or more. These printers don’t really need
much more buffering and can be driven
directly from a parallel port without any fan-
cy programming.

A buffer would really be useful to drive a
122 Microcomputing, October 1980

serial printer, especially a slow one. For in-
stance, a IK buffer on a 110-baud tele-
printer would hold 100 seconds of output,
allowing a program to get 100 seconds
ahead of the printer This can be most im-
pressive if you list a program on the printer,
and can go on to something else while the
printer is still listing.

The programming needed to do this is
easy to use. Included in this article are two
versions of such an interrupt-driven printer
driver. Both require an MP-S port on port 1,
having a jumper in the IRQ position to
enable interrupts.

Listing 1 shows a simple routine that pro-
vides only a 256-byte buffer and is intended
to sit in a high RAM memory address such
as A800. It essentially consists of three
parts.

An INITLZ routine must be called before
any output to the printer driver is per-
formed, and it sets up some pointers and
flags, puts the address of the interrupt ser-
vice subroutine (ISS) into the IRQ vector at
A000 and returns to the calling program.

The routine uses a 256-byte buffer in
memory, and two pointers are used to keep
track of buffer locations. INPTR always
points to the next empty location in the buf-
fer that can be filled with an incoming
character, while OUTPTR always points to
the next character to be printed. The buffer
is looped back on itself, so that when the
last location is filled or emptied, the next
location to be filled or emptied is at the
beginning again. It resembles a never-
ending photo slide tray, with the pointer
continuously cycling through the buffer.

Whenever INPTR and OUTPTR are the
same, the buffer is empty; whenever
OUTPTR is equal to INPTR + 1, the buffer is
full. These tests are used by the program to
keep track of what is going on.

BUSYFL is a flag that indicates whether
the ACIA is busy. Each time a character is
sent out to the ACIA, BUSYFL is set to 1. It
stays at 1 until the ACIA finishes printing
and generates an IRQ interrupt to ask the
processor for another character, at which
time it goes back to 0. Thus, 1 in BUSYFL
means that the ACIA has started printing a
character, but hasn’t yet finished it.

The second part of the program is the IN-
PUT routine, which is designed as a replace-
ment for INEEE and is needed because IN-
EEE in most monitors reconfigures the
ACIA on port 1 to turn off interrupts. This
would stop all printing if allowed, so INPUT
does the same thing, but without the ini-
tialization.

The main part of the program is the OUT-
PUT routine, which replaces OUTEEE. This
routine was designed for use with standard
programs such as BASIC, and so OUTPUT
has some features that allow it to complete
printing if BASIC returns to the monitor.

(The monitor’s calling INEEE would other-
wise stop printing even if there was still
some data in the buffer, because INEEE
normally initializes the ACIA to turn off its
interrupt system.)

This is done by putting into the calling
program a print of a control-F at the end of
output; in BASIC, this is done with PRINT
CHR$(6). After this, the OUTPUT driver
waits until the buffer is empty before return-
ing to the calling program. This prevents the
loss of the material in the buffer. Because
of the way INPTR and OUTPTR are handled
in this routine, this program cannot be
placed in ROM.

Listing 2, on the other hand, shows
another version of this program. This ver-
sion is in ROM and is part of the HUMBUG
monitor I described in the September 1980
Microcomputing.

In this version, the buffer is a IK RAM
area at D400 to D7FF. Because ten bits are
now needed to point to a specific location in
the buffer (as opposed to eight bits when
the buffer was just 256 bytes long), INPTR
and OUTPTR are now two bytes instead of
one, and this complicates the program-
ming. The INITLZ routine starts with a ten
millisecond time delay to permit the ACIA
on port 0 to finish any current operation and
then clears INPTR, OUTPTR, POST AT (the
flag used by FCROM in the main monitor to
steer non-interrupt output to port 0) and
BUSYFL. Then it places the address of the
ISS routine in the IRQ location of monitor
RAM (at A000), puts a nonzero number into
IRQON to indicate that initialization has
been done and exits.

Just in case non-monitor programs want
to use this routine, entry point IQPRNT is in-
cluded just after the initialization routine.
This entry is used by all such programs and
automatically initializes whenever a
control-E (hex 05) is printed. Otherwise, it
falls through to OUTPUT.

Flex

Flex 2.0 uses SWI interrupts to handle its
printer spooling feature. It changes the
SWIJMP vector at A012 and does not
restore it when done. Be careful if you try to
debug a machine-language program with
breakpoints after using Flex 2.0, since
breakpoints wi|l now return to Flex 2.0 in-
stead of to your monitor.

Converting programs from miniFlex to
Flex 2.0 or back is generally not too difficult.
Basically, any machine-language program
that uses disk operations maintains a file
control block, or FCB, for every open disk
file. In miniFlex, this FCB contains a total of
192 bytes — 64 bytes of status control info,
followed by 128 bytes for the contents of
one disk sector. Since Flex 2.0 has 256
bytes per sector, its FCB is 320 bytes long
(64 + 256). The organization of the data in

Listing 1. Self-contained serial printer driver.

MAM SPEEDUP

* INPTR POINTS TO THE NEXT EMPTY LOCATION IN BUFFER

* OUTPTR POINTS TO THE NEXT LOCATION TO BE OUTPUT

* IF INPTR=QUTPTR, BUFFER IS EMPTY

* IF OUTPTR=INPTR+1 BUFFER IS FULL

* BUSYFL INDICATES WHETHER ACIA IS BUSY

* BUS YFL= 1 MEANS ACIA HAS BEEN STARTED ON OUTPUT,

* BUT INTERRUPT INDICATING COMPLETION HAS

* NOT YET ARRIVED

* MONITOR AND I/O EQUATES

(E1D1)

0UTEEE

EQU

♦ei r i

(E07E)

PDATA

EQU

♦E07E

(EODO)

NONITR

EQU

♦ EODO

(8004)

ACIACR

EQU

♦8004

(8005)

ACIADR

EQU

ACIACR+1

( A000 )

IRQPTR

EQU

♦A000

( A800 )

0RG

♦ A800

* TRANSFER

VECTORS INTO SPEEDUP

A800

7E

A82E

VECTOU

JMP

OUTPUT

A803

7E

A820

VECTIN

JNP

INPUT

A806

7E

A809

VECTIZ

JNP

INITLZ

* INITIALIZE

ROUTINE

AB09

B6

8004

IMITLZ

LDA

A

ACIACR

IN CASE ACIA IS BUSY, UAIT

A80C

47

ASR

A

FOR CURRENT OPERATION TO COMPLETE

A80D

47

ASR

A

A80E

24

F9

BCC

INITLZ

A8 1 0

7F

A86B

CLR

INPTR

INITIALIZE INPUT AND OUTPUT PTRS

A81 3

7F

A890

CLR

OUTPTR

A81 6

7F

A8F4

CLR

BUSYFL

ACIA NOT BUSY

A819

C£

A876

LDX

BISS

POINTER TO ISS ROUTINE

A81C

FF

A000

STX

IRQPTR

INSERT IRQ TRANSFER ADDRESS

A81F

39

RTS

AND RETURN

* INPUT FROM

TERMINAL

ROUTINE (NO INTERRUPTS USED)

A820

B6

8004

INPUT

LDA

A

ACIACR

UAIT FOR CHARACTER

A823

47

ASR

A

A824

24

FA

BCC

INPUT

A826

B6

8005

LDA

A

ACIADR

GET THE CHARACTER

A829

8D

03

BSR

OUTPUT

ECHO IT

A82B

84

7F

AND

A

BI7F

STRIP OFF PARITY BIT

A82D

39

RTS

* OUTPUT TO TERMINAL

ROUTINE

A82E

81

06

OUTPUT

CMP

A

• ♦06

END OF DATA?

A830

27

15

BEQ

DONE

YES

A832

01

NOP

A833

OF

SEI

DISABLE INTERRUPT SYSTEM

A834

7B

A8F4

TST

BUSYFL

IS ACIA BUSY?

A837

26

IB

BNE

BUSY

YES

A839

B7

8005

FREE

STA

A

ACIADR

NO; ACIA IS FREE SO LET'S OUTPUT

A83C

7 C

A8F 4

INC

BUSYFL

TURN ON BUSY FLAG

A83F

86

35

LDA

A

N 435

ENABLE ACIA TRANSMITTER FOR IRQ

A841

B7

8004

STA

A

ACIACR

A844

01

NOP

A845

OE

CL I

ENABLE INTERRUPTS

A846

39

RTS

AND RETURN TO MAIN PROGRAM

♦ IF BONE,

CLEAN UP AND RETURN

A847

7D

A8F4

DONE

TST

BUSYFL

UAIT FOR BUFFER TO EMPTY

A84A

26

FB

BNE

DONE

A84C

86

15

LDA

A

♦♦15

DISABLE ACIA TRANSMITTER INTERRUP

A84E

•7

8004

STA

A

ACIACR

A851

01

NOP

A852

OF

SEI

DISABLE INTERRUPTS

A853

39

RTS

* ACIA

IS BUSY, SO STORE IN BUFFER

A854

37

BUSY

PSH

B

A855

F6

A86B

BUSY1

LDA

B

INPTR

IS BUFFER FULL?

A858

5C

INC

B

A859

FI

A890

CMP

B

OUTPTR

A85C

26

04

BNE

N0TFUL

♦ FULL,

, SO

UAIT UNTIL

SOME SPACE IS AVAILABLE

A85E

01

NOP

A85F

OE

CLI

ENABLE INTERRUPTS

A860

20

F3

BRA

BUSY1

GO BACK AND CHECK AGAIN

* NOT FULL,

, SO STORE

CHARACTER IN BUFFER

A862

01

N0TFUL

NOP

A863

OF

SEI

DISABLE INTERRUPTS IF ENABLED ABO'

A864

FF

A8F2

STX

SAVEX

SAVE INDEX REGISTER

A867

CE

A8F5

LDX

•BUFFER

( A86B )

INPTR

EQU

*♦1

CAUTION - NOT PROMMABLE

A86A

A7

00

STA

A

o,x

STORE INTO NEXT EMPTY BUFFER LOC

A86C

7C

A86B

INC

INPTR

INCREMENT IN POINTER

A86F

01

NOP

A870

OE

CLI

ENABLE INTERRUPTS

A871

33

PUL

B

RESTORE B AND INDEX

A872

FE

A8F2

LDX

SAVEX

A875

39

RTS

RETURN

♦INTERRUPT

SERVICE ROUTINE

A876

B6

8004

1SS

LDA

A

ACIACR

DID SOMETHING ELSE INTERRUPT?

A879

2A

20

BPL

ERROR

IF YES

♦ OK - INTERRUPT CAME FROM ACIA

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v* Reader Sen/ice index— page 241

Microcomputing, October 1980 123

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A87B

7F

A8F4

CLR

BUSYFL

ACIA NO LONGER BUSY.

A87E

B6

A86B

LDA

A

INPTR

IS THE BUFFER EMPTY?

A881

B1

A890

CMP

A

OUTPTR

A884

26

06

BNE

NOTEMT

NO

A886

86

15

LDA

A

Ml 5

DISABLE ACIA TRANSMITTER INTERRUPTS

A888

B7

8004

STA

A

ACIACR

A88B

3B

RTI

RETURN

* BUFFER NOT

EMPTY, SO

OUTPUT THE NEXT CHARACTER

A88C

CE

A8F5

NOTEMT

LDX

RBUFFER

( A890 )

OUTPTR

EQU

*+1

CAUTION - NOT PROMMABLE

A88F

A6

00

LDA

A

o,x

GET NEXT CHARACTER

A891

B7

8005

STA

A

ACIADR

OUTPUT IT

A894

7C

A890

INC

OUTPTR

INCREMENT OUTPUT POINTER

A897

7C

A8F4

INC

BUSYFL

ACIA IS BUSY AGAIN

A89A

3B

RTI

RETURN TO PROGRAM

♦ ERROR ROUTINE - INTERRUPT NOT CAUSED BY ACIA

A89B

86

15

ERROR

LDA

A

Ml 5

DISABLE ACIA INTERRUPTS

A89D

B7

8004

STA

A

ACIACR

A8A0

B6

A86B

ERR0R1

LDA

A

INPTR

SEE IF BUFFER IS EMPTY

A8A3

B1

A890

CMP

A

OUTPTR

A 8 A A

27

13

BEQ

EMPTY

YES

A8A8

B6

A890

LDA

A

OUTPTR

NO, SO EMPTY IT BEFORE QUITTING

A8AB

B7

A8B2

STA

A

GETCHR

A8AE

CE

A8F5

LDX

NBUFFER

( A8B2)

GETCHR

EQU

•4+1

CAUTION - NOT PROMMABLE

A8B1

A6

00

LDA

A

0,X

GET NEXT CHARACTER

A8B3

BD

E1D1

JSR

OUTEEE

PRINT IT

A8B6

7C

A890

INC

OUTPTR

INCREMENT POINTER

A8B9

20

E5

BRA

ERR0R1

GO BACK AND TEST AGAIN

♦BUFFER EMPTY, SO PRINT ERROR MESSAGE AND QUIT

A8BB

CE

A8C4

EMPTY

LDX

NERRHSG

A8BE

BD

E07E

JSR

PDATA

PRINT ERROR MESSAGE

A8C1

7E

EODO

JMP

MONITR

RETURN TO MONITOR

A8C4

OD

ERRMSG

FCB

$D , $ A , 0 , 0

,0,0

A8CA

45

FCC

/ERROR -

INTERRUPT NOT CAUSED BY ACIA /

A8F 1

04

FCB

$04

♦ DATA

ETC

A8F2

SAVEX

RMB

2

INDEX STORAGE

A8F 4

BUSYFL

RhB

1

ACIA BUSY FLAG

A8F5

BUFFER

RMB

256

256-BYTE BUFFER

END

* PORT 0 PRINTER INTERRUPT DRIVERS

* INPTR POINTS TO THE NEXT EMPTY LOCATION IN BUFFER

* OUTPTR POINTS TO THE NEXT LOCATION TO BE OUTPUT

* IF INPTR=OUTPTR, BUFFER IS EMPTY

* IF 0UTPTR=INPTR+1 BUFFER IS FULL

* BUSYFL INDICATES UHETHER ACIA IS BUSY

* BUSYFL*! MEANS ACIA HAS BEEN STARTED ON OUTPUT,

* BUT INTERRUPT INDICATING COMPLETION HAS

* NOT YET ARRIVED

* INITIALIZE ROUTINE

ECCF

FF

D04A

INITLZ STX

SAVEDX

ECD2

CE

04E2

LDX

M04E2

ECD5

09

INUAIT DEX

UAIT ABOUT 10 MILLISEC

ECD6

26

FD

BNE

INUAIT

FOR ACIA TO FINISH IF BUSY

ECD8

CE

0000

LDX

10

ECDB

FF

D051

STX

INPTR

ECDE

FF

D053

STX

OUTPTR

RESET INPUT AND OUTPUT POINTERS

ECE1

7F

DOOO

CLR

POSTAT

TURN OFF NORMAL PORT 0 OUTPUT

ECE4

7F

D050

CLR

BUSYFL

ACIA NOT BUSY

ECE7

CE

ED60

LDX

mss

RESET IRQ POINTER ADDRESS TO ISS

ECEA

FF

AOOO

STX

IRQ

ECED

7F

D05A

CLR

IRQON

ECFO

7C

D05A

INC

IRQON

TURN ON IRQ IN PROGRESS FLAG

ECF3

FE

D04A

LDX

SAVEDX

ECF6

39

RTS

AND RETURN

• NON-MONITOR ENTRY

POINT

ECF7

81

05

IQPRNT CMP

A

M05

ON CONTROL-E, GO INITIALIZE

ECF9

27

D4

BEQ

INITLZ

OTHERWISE FALL THROUGH TO OUTPUT

♦ OUTPUT TO TERMINAL

ROUTINE

ECFB

81

06

OUTPUT CMP

A

M06

END OF DATA?

ECFD

27

15

BEQ

DONE

YES

ECFF

01

NOP

NO

EDOO

OF

SEI

DISABLE INTERRUPT SYSTEM

ED01

7D

D050

TST

BUSYFL

IS ACIA BUSY?

ED04

26

IE

BNE

BUSY

YES

ED06

B7

8001

FREE STA

A

ACIADR

NO; ACIA IS FREE SO LET'S OUTPUT

ED09

7C

D050

INC

BUSYFL

TURN ON BUSY FLAG

EDOC

86

35

LDA

A

M35

ENABLE ACIA TRANSMITTER FOR IRQ

EDOE

B7

8000

STA

A

ACIACR

ED1 1

01

NOP

EDI 2

OE

CLI

ENABLE INTERRUPTS

EDI 3

39

RTS

AND RETURN TO MAIN PROGRAM

• IF DONE,

CLEAN UP

AND RETURN

EDI 4

7D

D050

DONE TST

BUSYFL

WAIT FOR BUFFER TO EMPTY

EDI 7

26

FB

BNE

DONE

EDI 9

86

15

LDA

A

M15

DISABLE ACIA TRANSMITTER INTERRUPTS

ED1B

B7

8000

STA

A

ACIACR

ED1E

01

NOP

EDI F

OF

SEI

DISABLE INTERRUPTS

124 Microcomputing, October 1980

Listing 2. ROM able printer driver with IK buffer.

the first 64 bytes is the same in both
systems, so changing from one Flex to the
other involves just changing the size of the
FCB.

A second change involves the addresses
of Flex routines. MiniFlex is located
at addresses 7000-7FFF, while Flex 2.0 is at
A080-BFFF. Thus, all references to these
locations must be changed. See Table 1 for
a fairly complete list of equivalents be-
tween the two. Mini-Flex does not keep the
date as Flex 2.0 does, so changing from
Flex 2.0 back to miniFlex may require delet-
ing all references to dates.

Finally, there is a slight difference in how
the two systems handle the SETEXT
subroutine. When this routine is executed,
miniFlex changes the contents of the index
register, while Flex 2.0 doesn’t. Thus, if you
are converting a program from Flex 2.0 back
to miniFlex, you may want to save index
register contents before jumping to
SETEXT and then restore it.

While converting programs from Flex 2.0
back to miniFlex may not be common, I
tried it recently to convert Programma’s
SPL/M compiler. The conversion was sim-
ple.

Next Time

A review and detailed comparison of the
SPL/M compiler with several others (Mi-
croware’s ABASIC, SSB’s FORTRAN and
Hemenway’s STRUBAL + ) will appear in up-
coming installments.*

Naae

Flex 1 & 2
Address

MiniFlex

Address

LINBUF

A080

7000

FCB

A840

7740

EOLCHR

AC02

7082

MONTH

ACOE

-

DAY

ACOF

-

YEAR

AGIO

-

LSTERH

AC1 1

7091

LINPTR

AC14

7094

CURCHR

AC1 8

709A

COLDS

ADOO

7100

WARMS

AD03

7103

RENTER

AB06

7106

0UTCH2

AD12

7136

GETCHR

AD 1 5

71 OF

PUTCHR

ADI 8

7112

INBUFF

ADI B

7115

PSTRNG

ABIE

7118

CLASS

AB21

71 1 B

PCRLF

A 1)24

71 1 E

NXTCH

AD27

7121

RSTRIO

AB2A

7124

GETFIL

AD2D

7127

LOAD

AD30

712A

SETEXT

AD33

71 2D

ABDBX

AD36

7130

OUTBEC

AD39

7133

OUTHEX

AD3C

7139

RPTERR

AD3F

713C

GETHEX

AD42

71 3F

OUTABR

AD45

-

INDEC

AD48

-

DOCMND

AD4B

7142

HE X AD J

B1V8

74BA

QPREAD

B2A4

758A

FMSCLS

B403

7803

FMS

B406

7806

Table 1. Flex routine addresses.

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If you work with large computers, ELF II and the Short Course will help you
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Plug in the GIANT BOARD to record and play back programs, edit and
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ELF II add ons already include the ELF II Light Pen and the amazing ELF BUG
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The ELF-BUG Monitor lets you debug programs with lightening speed because
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The incredible ELF II Light Pen lets you write or draw anything you want on a
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ELF II Tiny BASIC

Ultimately, ELF II understands only machine language-the fundamental coding
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Now Available! Text Editor, Assembler,

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ELF Il's Assembler translates assembly language programs into hexidecimal
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U Video Display Board kit lets you generate a sharp,
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$14 95 postpaid

□ Text Editor on cassette tape gives you the ability to
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while they are displayed on your video monitor (Add
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□ Assembler on cassette tape translates assembly
language programs into hexidecimal machine code for
ELF II use Mnemonic abbreviations lor instructions
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$19 95 on cassette tape

SAVE S9 90— Text Editor. Assembler & Disassembler
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Coming Soon: A-D. D-A Converter. Controller Board

and more 1

Print

Name

City _
Slate _

CALL TOLL FREE: 800 243-7428 i

_ _ DEALER INQUIRIES INVITED

iS Reader Service index— page 241

Microcomputing, October 1980 125

MARK GORDON

COMPUTERS

DIVISION OF MARK GORDON ASSOCIATES, INC. ^84

15 KENWOOD ST., CAMBRIDGE, MASSACHUSETTS 02139
(617)491-7505

SORT-80

Produced exclusively for
Mark Gordon Computers by SBSG

TRS-80* disk files may be sorted and merged
using SORT-80, the general purpose, machine
language, sort program. Written in assembly
language for the Z-80 microprocessor, it can:

—Sort files one disk in length
—Sort Direct Access, Sequential Access and
Basic Sequential Access files
—Reblock and print records

— Recontrol files from disk

— Be executed from DOS
—Be inserted in the job stream
—Allow parameter specification

• input/output file specification

• input/output record size

• lower/upper record limit

• print contents of output file

• input/output file key specifiers

The minimum requirement is a 32K TRS-80*
Level II computer with one disk drive or a sin-
gle drive Model II computer. It will operate on
35, 40 and 77 track drives, and has been tested
on TRSDOS 2,1, 2.2, 2.3, NEWDOS 2.1, 3.0 and
VTOS 3.0.1. It is compatible with most ma-
chine language printer drivers. Sort time is
fast: for example, a 32K file will sort in approxi-
mately 40 seconds. $59.

InfoBox is the easiest-to-use information man-
ager available for the TRS-80*. It’s ideal for
keeping track of notes to yourself, phone num-
bers, birthdays, inventories, bibliographies,
computer programs, music tapes, and much
more. This fast assembly language program
lets you enter free-format data, variable length
items and lets you look up items by specifying
a string of characters or words that you want
to find. You can also edit and delete items.
Items entered into InfoBox can be written to
and read from cassette and disk files. All or
selected items can be printed on a parallel or
serial printer. InfoBox occupies 3K. Specify
cassette or disk version. $29.95

*TRS*80 is a Tandy Corp. Trademark

ED20

7 F

D05A

CLR

IRQON

TURN OFF CURRENT IRQ OUTPUT FLAG

ED23

39

RTS

♦ ACIA IS BUSY, SO STORE IN BUFFER

ED24

37

BUSY PSH

B

ED25

FF

D048

STX

SAVEX

SAVE INDEX REGISTER

ED28

FE

D051

BUSY1 LDX

INPTR

IS BUFFER FULL?

ED2B

08

I NX

ED2C

8C

0400

CPX

MI0400

FIX OVERFLOW OVER IK

ED2F

26

03

BNE

BUSY2

ED31

CE

0000

LDX

*$0000

ED34

BC

D053

BUSY2 CPX

0UTPTR

ED37

26

04

BNE

N0TFUL

♦ FULL, SO

WAIT UNTIL

SOME SPACE IS AVAILABLE

ED39

01

NOP

ED3A

OE

CLI

ENABLE INTERRUPTS

ED3B

20

EB

BRA

BUSY1

GO BACK AND CHECK AGAIN

♦ NOT FULL,

, SO STORE CHARACTER IN BUFFER

ED3D

01

N0TFUL NOP

ED3E

OF

SEI

DISABLE INTERRUPTS IF ENABLED ABOVE

ED3F

FE

D051

LDX

INPTR

ED42

BD

ED97

JSR

FINDCH

GO TO FIND INPTR L0C IN BUFFER

ED45

A7

00

STA

A

0,X

STORE INTO NEXT EMPTY BUFFER L0C

ED47

B6

D051

LDA

A

INPTR

ED4A

F6

D052

LDA

B

INPTR+1

ED4D

CB

01

ADD

B

*1

INCREMENT IN POINTER

E051

84

03

AND

A

M$03

MASK TO LIMIT TO IK

ED53

B7

D051

STA

A

INPTR

ED56

F7

D052

STA

B

INPTR+1

ED59

01

NOP

ED5A

OE

CLI

ENABLE INTERRUPTS

EB5B

33

PUL

B

RESTORE B AND INDEX

ED5C

FE

D048

LDX

SAVEX

ED5F

39

RTS

RETURN

♦INTERRUPT

SERVICE ROUTINE

ED60

B6

8000

ISS LDA

A

ACIACR

DID SOMETHING ELSE INTERRUPT?

ED63

2A

4B

BPL

ERROR

IF YES

♦ OK - INTERRUPT CAME

FROM ACIA

ED65

7F

D050

CLR

BUSYFL

ACIA NO LONGER BUSY.

ED68

FE

D051

LDX

INPTR

IS THE BUFFER EMPTY?

ED6 B

BC

D053

CPX

0UTPTR

ED6E

26

06

BNE

N0TENT

NO

ED70

86

15

LDA

A

M$15

DISABLE ACIA TRANSMITTER INTERRUPTS

ED72

B7

8000

STA

A

ACIACR

ED75

3B

RTI

RETURN

♦ BUFFER NOT

EMPTY, SO

OUTPUT THE NEXT CHARACTER

ED76

FE

D053

N0TEMT LDX

0UTPTR

ED79

BD

ED97

JSR

FINDCH

GO FIND 0UTPTR CHAR IN BUFFER

ED7C

A6

00

LDA

A

0,X

GET NEXT CHARACTER

ED7E

B7

8001

STA

A

ACIADR

OUTPUT IT

ED81

B6

D053

LDA

A

0UTPTR

ED84

F 6

D054

LDA

B

OUTPTR+1

ED87

CB

01

ADD

B

Ml

INCREMENT OUT POINTER

ED89

89

00

ADC

A

NO

ED8B

84

03

AND

A

M$03

MASK TO LIMIT TO IK

ED8D

B7

D053

STA

A

0UTPTR

ED90

F7

D054

STA

B

0UTPTR+1

ED93

7C

D050

INC

BUSYFL

ACIA IS BUSY AGAIN

ED96

3B

RTI

RETURN TO PROGRAM

♦ FINDCH -

ADD POINTER

TO BUFFER ADDR

ED97

FF

D055

FINDCH STX

TEMP

SAVE POINTER

ED9A

36

PSH

A

AND SAVE CHARACTER

EB9B

B 6

D055

LDA

A

TEMP

ED9E

F 6

D056

LDA

B

TEMP+1

ED A 1

CB

00

ADD

B

MBUFFER

ADD BUFFER ADDR TO POINTER

EDA3

89

D4

ADC

A

N8UFFER/256

EDA5

B7

D055

STA

A

TEMP

EDA8

F7

D056

STA

B

TEMP+t

SAVE NEU ADDRESS

EBAB

FE

D055

LDX

TEMP

PUT INTO INDEX REG

EDAE

32

PUL

A

RESTORE CHARACTER

EDAF

39

RTS

* ERROR ROUTINE - INTERRUPT NOT CAUSED BY ACIA

EDBO

86

15

ERROR LDA

A

Nil 5

DISABLE ACIA INTERRUPTS

EDB2

B 7

8000

STA

A

ACIACR

EDB5

FE

D051

ERR0R1 LDX

INPTR

SEE IF BUFFER IS EMPTY

EDB8

BC

D053

CPX

0UTPTR

EDBB

27

IF

BEQ

EMPTY

YES

EDBD

FE

D053

LDX

0UTPTR

NO, SO EMPTY IT BEFORE QUITTING

EDCO

BB

ED97

JSR

FINDCH

FIND 0UTPTR CHAR IN BUFFER

EDC3

A6

00

LDA

A

o,x

GET NEXT CHARACTER

EDC5

3D

FC0C

JSR

0UTEEE

PRINT IT

EDC8

B6

D053

LDA

A

0UTPTR

EDCB

F 6

D054

LDA

B

OUTPTR+1

EDCE

CB

01

ADD

B

Ml

INCREMENT OUT POINTER

EDDO

89

00

ADC

A

NO

EDD2

84

03

AND

A

M$03

MASK TO LIMIT TO IK

EDD4

B7

D053

STA

A

0UTPTR

EPD7

F7

D054

STA

B

OUTPTR+1

EDDA

20

D9

BRA

ERROR 1

GO BACK AND TEST AGAIN

♦BUFFER EMPTY, SO PRINT ERROR HESSA6E AND QUIT

EDDC

CE

EDE5

EMPTY LDX

NERRMS6

EDDF

BD

FC1 2

JSR

PDATA

PRINT ERROR HESSA6E

EDE2

7E

FC03

JMP

UARHST

RETURN TO MONITOR

EDE5

OB

ERRMSG FCB

$D,$A,0,0

,0,0

EDEB

45

FCC

/ERROR -

IRQ NOT FROM ACIA/

EE04

04

FCB

104

126 Microcomputing, October 1980

CompuServe’s

information

service.

A world of

information

available.

Right now.

If you have a personal computer — or a computer
terminal — CompuServe can bring a world of
information into your home or small business.

CompuServe

CompuServe is a major computer services com-
pany that has been serving top industrial and
governmental clients for more than a decade.
Now we’re also applying our extensive computing
capacity to the delivery of information services to
your personal computer.

The Information Service

This exciting service is available in more than 250
cities between 6 p.m. and 5 a.m. weekdays, all
day weekends and most holidays. Cost? Only
$5.00 per hour billed in minutes. All you need is a
300 baud modem, and our complete information
service is only a local phone call away.

Welcome to CompuServe’s information service.

• News. Weather. Sports. Major regional news-
papers. Plus international news services.

• Finance. MicroQuote. Updates and historical
information on stocks, bonds and commodities.

• Entertainment. Theatre, book, movie and res-
taurant reviews. Plus opera, symphony, ballet,
dance, museums, galleries...

• Electronic Mail. Create, edit, send and receive
messages from any other CompuServe user...
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• Home & Educational Reference Service. Any-
thing you want to know... from encyclopedia in-
formation to household tips.

• CompuServe User Information. In case you
need technical help ... and information on new
services as they become available.

• Micro NET. For the computer hobbyist. Software
Exchange, line printer art gallery, challenging
games, programming languages, word proces-
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And this is just the beginning. CompuServe is
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The world of electronic information isn’t coming
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CompuServe is Available at
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Your local Radio Shack® Store Sells Com-
puServe’s information service. There are more
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Radio Shack is a division of Tandy Corporation.

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5000 Arlington Centre Blvd.

Columbus, Ohio 43220
(614) 457-8600

i/ 0 Reader Service index— page 241

Microcomputing , October 1980 127

Speed Up Your BASIC Programs

Simple techniques do make a difference; they can work for you, too.

1 FOR A = BTOC

2.8

2 NEXT

i.i

3 NEXT A

1.5

4 REM

0.4

5 DATA 1

0.4

6 RESTORE

0.4

7 A = A

1.4

8 A = 1

2.0

9 each additional digit

1.1

10 BB = 1

2.1

1 1 each additional character

0.1

12 GO TO 3

0.9

13 GOSUB. .. RETURN

1.2

14 PRINT

72

15 PRINTA

80

16 PRINT A$ where A$ = “A”

72

17 each additional character

0.3

18 C = FNA(B)

3.6

19 C = A + BorC = A- B

2.6

20 each additional + A

1.1

21 C = A*BorC = A/B

3.4

22 each additional • A

1.8

23 IF C THEN 5 where C = A<B is false

1.2

24 C = A<B is false

2.9

25 IF A<B THEN 5 false

2.5

26 : for 2 statements on a line 0.1 saved

27 space in a line

0.03

28 examine 1 entry in variable table

0.03

29 A = SQR(B)

39

30 A = SIN(B) or A = COS(B)

22

31 A =TAN(B)

39

32 A = ATN(B)

27

33 A = EXP(B)

22

34 A = LOG(B)

16

35 A = BC

39

36 A = B ANDC

4.0

37 A = BORC

4.0

38 C = NOT A

2.9

39 A = USR(B)

2.3

40 A = LEN(B$)

2.6

41 A = ASC(A$)

2.4

42 A$ = LEFT${B$ l 1)or MID or RIGHT

4.5

43 A$ = CHR$(B)

2.8

44 A$ = STR$(B)

7.9

45 A = VAL(B$)

3.3

Table 1. Time (in ms) for BASIC to pro-

cess each statement or fraction

of a

statement. Lines 12 and 13 reflect mini-

mum times, since the times depend on

how many numbers are examined. SIN

functions, for example, may vary with

the value of the argument. Line 26 shows

the time saved for two lines of code. For

all entries, the times may depend on how

the statement is used.

Edward H. Carlson
3872 Raleigh Dr.
Okemos, Ml 48864

T he secrets of speeding up BASIC are
simple once you analyze how it goes
about its work. Best of all, you may need to
change only a small portion of the code to
make it run faster.

This article’s examples are for the
Microsoft BASIC-1 N-ROM, Version 1.0, Rev.
3.2, used on my OSI C2-4P and other Ohio
Scientific computers. A similar Microsoft
BASIC is used on the PET and the TRS-80. In
fact, most BASIC interpreters should be-
have in a similar way. This article describes
procedures you can use to check out your
own machine.

Typically, a program spends much of its
time in a small fraction of its total code.
This is especially true when nested loops
are present. The running time of the pro-
gram is sensitive to the efficiency of the in-
nermost loop.

Speed and Clarity

The BASIC interpreter decodes and ex-
ecutes one line of source code at a time,
perhaps even branching out of the line
before reaching its end. Within a line, the in-
terpreter reads and decodes each character
in turn. The fewer lines and characters the

program has, the faster the interpreter can
work.

Before you go on a binge condensing
your code, remember that a good program
has other essential characteristics besides
speed. One of the most important is clarity.
This is effected in several ways that are the
opposite of condensation: for example,
long, descriptive variable names, spaces
between words, many Remark statements
and the use of subroutines to emphasize
the logical structure of the program.

So if your program has nested loops, or
otherwise spends most of its time in a small
portion of the code, then only that code
need be condensed. The rest can be written
with clarity as the prime consideration (if
space in memory is not also a problem).

Besides condensing your code to obtain
speed, you must also realize that BASIC
uses and stores its numbers in binary form
and so needs to decode the decimal form
that occurs in the source code. It must do
this each time it reinterprets a line; it never
remembers that it has decoded the number
before. Assign and use names for any such
decimal constants, and your programs will
be greatly speeded up.

For example, Listing 1 shows three ver-
sions of a program to fill my computer’s
screen with the letter A. Version a runs in 25
seconds, but version b, which avoids
repeated decoding of the decimal numbers,
runs in ten seconds. Version c is the fastest,
running in eight seconds.

It is important to note that the FOR state-
ment is only interpreted once during the
loop — at the beginning- while the NEXT
statement is executed each time the in-
terior of the loop is traversed to test for
completion of the loop. So optimization of
the FOR statement is not valuable in
speeding up your program.

Other “slowpokes” in BASIC include the
statements that reassign the flow of execu-

128 Microcomputing, October 1980

10

FOR 1=0 TO 2047

20

POKE 53248+1 , 65

30

NEXT

Listing la.

5 0=53248
7 R=65

10 FOR 1=0 TO 2047
20 POKE Q+I - R
38 NEXT

Listing 1b.

5

0=53248 :B=65

10

F ORR=QT 00+2047 : POKER . B : NEXT

Listing 1c.

tion, such as GO TO, GOSUB and
ON... GOTO. They can be speeded up,
however. They start searching for their
target line number at the lowest-numbered
line in the source program and spend 0.85
milliseconds per line. This can add up to a
large amount of time in a long program.

Instead of starting a program with the
one-time-only housekeeping statements,
continuing with the central structure and
ending with the subroutines, I start my pro-
grams with a jump to high line numbers,
where I put the initializing and housekeep-
ing statements.

The main body of the program is written
next, starting at lower line numbers but still
high enough to leave plenty of room at the
beginning for all the subroutines (or at least
the ones called from time-sensitive inner
loops). Another advantage is that the
decimal addresses in the GOSUB
statements will have fewer digits and will be
decoded quicker.

Searching the Variable Table

When RUN is hit and execution of the pro-
gram starts, there is no variable table. It is
created by the interpreter as it scans lines.
Each time a variable name is found, the vari-
able table is searched. If the variable name
is not already in the table, it is added at the

end of the table.

BASIC always searches the table in order
from the first-encountered to the last-en-
countered variables. Your most-used vari-
ables should be placed at the beginning of
the table by executing a statement early in
the program that defines the desired vari-
ables, such as X = 0: Y = 0: Z = 0.

The variable table search is efficient
(probably because BASIC knows that each
entry is exactly six bytes long). The time
spent is only 0.03 milliseconds per entry ex-
amined. This is about the same time spent
ignoring a space in decoding a line of
source code. Paying attention to the vari-
able table will probably not speed up your

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Subroutines

It is more effective to place several
statements on one line by separating them
with a colon (in OSI BASIC). A time savings
of 0.1 milliseconds is achieved each time
such a colon is encountered. A space sav-
ings of three bytes is also achieved..

Using colons, short “subroutines” can be
written directly after an IF statement on the
same line, rather than using the IF. . .THEN
with a GOSUB to jump to a subroutine. This
saves time by omitting the search-for line
number and also gives a tight execution of
the “subroutine.” That portion of the state-
ment after THEN is not interpreted if the IF
condition was “false.”

Listing 2 shows two versions of the pro-
gram. Version a uses a proper subroutine,
while version b differs only in line 20, which

5 fi

=R: RETURN

10

FOR 3>0TO10000

20

IF R=1 THEN GOSUB 5

30

NEXT

40

END

100

R=1

110

GOTO 10

Listing 2a.

20 IFR=1THENR=R

Listing 2b.

has a “subroutine” on the same line with an
IF. (Both of these programs are executed
with “RUN100” to jump to the housekeeping
lines. Version b runs 1 2 seconds faster than

version a, or 1 .2 milliseconds saved for each
GOSUB. . .RETURN avoided.)

Summary

We have discussed the principles and the
most important applications for speeding
up BASIC. You can see from Listing 2 how
BASIC can be tested. A loop 10,000 turns
long is used to execute a statement. Then
the statement is replaced by one differing in
some feature.

By subtracting the running times, you
can find the difference in time to execute
the given feature of code. Table 1 gives the
running time for several BASIC statements
and portions of statements for the C2-4P
computer.

Listings 1 and 2 were made on a Com-
print 912 printer connected to the 6522 VIA
parallel port on the CPU board of the C2-4P
computer. ■

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i/ 0 Reader Service index— page 241

Microcomputing, October 1980 131

ENTER NOW! • GRAND PRIZE 16K LII TRS-80

Whoa, Apple

These two machine-language programs tighten the reins on galloping video displays.

Terry Edward Phillips
6011-4 Majors Lane
Columbia, MD 21045

A pple II is one of the fastest kids on the
block. When you list, DSP or trace a
BASIC program, the screen fills at an im-
pressive speed.

But this can sometimes be annoying and
frustrating. If you are trying to seriously
follow the information that’s being output,
not even a speed-reading course would
help.

Fortunately, two programs can easily
give you manual control over your output
rate. Both work well with Apple Integer, Ap-
plesoft (cassette or firmware) and the Apple
Monitor.

Introduction

Anything your Apple II displays on its
screen resides in a predetermined reserved
section of your Apple’s memory. Normally,
RAM locations 0400-07FF are used for
storage. This screen memory area, called
the primary page in the Apple manuals, is
continuously queried by hardware in your
Apple, which then generates the video
signals for your monitor.

Interestingly, this process is completely
unknown to the microprocessor. The CPU
has no idea that someone else is using its
memory. The system knows only that to
output video data, it must deposit the data
into this reserved area.

A machine-language subroutine located
in ROM at location FDFO places alpha-
numeric characters in the screen memory
area one at a time. This and subsequently-
called subroutines are responsible for plac-
ing the byte in the accumulator (passed by

the calling routine) into the screen memory,
adjusting the line width, line feeds and
scrolling and doing other housekeeping
chores.

The BASIC interpreter and Apple monitor
routines call this subroutine every time they
want to communicate with you via the
screen. For example, if your BASIC inter-
preter is executing a PRINT“APPLE” state-
ment, the interpreter will place the ASCII
code for the letter A in the accumulator and
go to the subroutine at FDFO. When it
returns from this subroutine (the letter A is
now on the screen), the code for the letter P
is then placed in the accumulator, and so
forth.

The BASIC interpreter and Apple monitor

do not go directly to the location FDFO to
output a character. Rather, they look at
RAM locations 0036, 0037 to find their out-
put subroutine. When the reset key is
pushed, the Apple monitor will, among
other tasks, place the address of the normal
video output routine, FDFO, into locations
0036, 0037. The calling routine then finds its
output subroutine by executing an indirect
jump to location 0036.

This means it jumps, not to location 0036,
but to the 16-bit address contained in loca-
tions 0036, 0037. Thus, the calling routine,
in a roundabout way, finds the normal video
output routine.

At first, this technique appears to be un-
necessarily complex. Why not have the in-

Address

Code

Label

Mnemonic

Comment

2 DC

A9

E5

LDA#E5

Place Delay Subroutine

2DE

85

36

STA 36

Address In locations

2E0

A9

02

LDA#02

0036, 0037

2E2

85

37

STA 37

2E4

60

RTS

2E5

08

ENTRY

PHP

Save relevant registers

2E6

48

PRA

2E7

18

FGCLR

CLC

Clear Flag

2E8

AD

00

CO

RKYBD

LDA C000

Read Keyboard

2 EE

10

OC

BPL FLGCK

Branch to Check Flag If
no key Is depressed

2 ED

2C

10

CO

BIT C010

Clear Keyboard Strobe

2F0

49

91

EOR#9 1

Mask for control keys

2F2

F0

F3

BEQ FGCLR

Branch to Clear Flag If
CTRL Q was depressed

2F4

29

FD

AND#FD

Mask for CTRL S key

2F6

DO

01

BNE FLGCK

Branch to Check Flag If
not CTRL S

2F8

38

SEC

Set Flag if CTRL S Is hit

2F9

B0

68

ED

FLOCK

BCS RKYBD

Branch to Read Keyboard
If Flag Is Set

2FB

PLA

Restore relevant registers

2FC

28

PLP

2FD

4C

F0

FD

EXIT

JMP FDFO

Jump to Normal Video
Output Subroutine

Program 1. Halts video output when the CTRL S key is depressed. Output is resumed
when the CTRL Q key is hit.

132 Microcomputing, October 1980

terpreter and monitor go directly to FDFO?
But this sleight of hand is useful. With this
indirect method, you can route output data
to any device, such as a printer, paper
punch or TTY, by placing the vector address
of the output routine designed for that par-
ticular device in locations 0036, 0037.

This technique of vectoring the output
offers a solution to the problem at hand.
You can change the vector address in loca-
tions 0036, 0037 from FDFO to the address
of a short routine whose only purpose is to
provide some sort of delaying tactic. After
the delay condition is satisfied, the
character in the accumulator is sent to the
normal video output subroutine located at
FDFO. The net effect is to reduce the speed
of video output.

Two Patches

Two short machine-language patches
are designed to provide a delay and give you
manual control over the speed of video out-
put.

The first program checks the keyboard
when a character is to be output to see if the
CTRL S key was depressed. If not, the nor-
mal output is continued. If the key was
depressed, the routine waits in a con-
tinuous loop until you depress the CTRL Q
key. Video output, therefore, can be
stopped and started by alternately striking
the CTRL S and CTRL Q keys respectively.

The second program is a bit different. It
uses game paddle 0 to determine the output
speed. When a character is to be output,
this program reads the value of paddle 0 via
a subroutine in ROM. This becomes the ini-

tial value of a two-stage timing loop. When
the counters in the loop are decremented to
zero, the loop is exited and the character is
passed to the normal output routine. This
variable timing loop allows you to vary the
output speed from approximately three
characters per second to nearly full speed,
just by varying the position of game paddle
0 .

Memory Location

Either routine, as presented, is assem-
bled at the top of page two of memory
(0200-02 FF). This area of memory is nor-
mally used by the Apple monitor as a
keyboard buffer. All your keystrokes be-
tween successive returns are stored here.
As long as you don’t type more than about
200 keys before hitting return, page two of
memory can be shared amicably between
the two functions. I decided to place the
routines there to avoid possible conflicts
with other software packages, but if its
location is inconvenient or undesirable, you
can relocate the programs elsewhere with
only minor changes.

The selected routine can initially be
entered into memory with the ROM-based
assembler described in the Apple manual.
Subsequent loads can be done via the tape
cassette, although they are short enough
that manual loading might be faster.

The selected routine is then initialized by
executing a call to 02DC in the monitor
mode or a CALL 732 in BASIC. You resume
normal video output by executing a ROM-
based subroutine with a call to FE93 or a
CALL - 365 in BASIC or when reset is hit. ■

Address

Code

Label

Mnemonic

Comment

2 DC

A9

E5

LDA#E5

Place Delay Subroutine

2DE

85

36

STA 36

Address In locations

2E0

A9

02

LDA#02

0036, 0037

2E2

85

37

STA 37

2E4

60

RTS

2E5

48

ENTRY

PHA

Save registers

2E6

98

TYA

2E7

48

PHA

2E8

8A

TXA

2E9

48

PHA

2EA

A2

00

LDX#00

Set Index for Paddle 0

2 EC

20

IE

FB

JSR PB1E

Subroutine to read Paddle

2EP

C8

INY

Adjust value of Paddle

2P0

98

TYA

Copy value Into A

2F1

AA

RSTRX

TAX

Restore value Into X

2F2

CA

INLOP

DEX

Inner delay loop

2F3

DO

PD

BNE INLOP

2F5

88

DEY

Outer loop decrement

2F6

DO

F9

BNE RSTRX

Restore Inner loop If

outer loop Is Incomplete

2F8

68

PLA

Restore registers

2F9

AA

TAX

2 PA

68

PLA

2PB

A8

TAY

2 PC

68

PLA

2FD

4C

P0

FD

EXIT

JMP FDFO

Jump to Normal Video

Output Subroutine

Program 2. Utilizes the game paddle 0 to vary the video output speed from approximate-
ly three characters per second to full speed.

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201/267-1117

v* Reader Service index— page 241

Microcomputing, October 1980 133

<75

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This 96-page workbook introduces the fundamentals of OSI
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* Includes Connector

Software available for the Rockwell AIM-65, MOS Technology
KIM-1, Synertek SYM-1, Motorola D2, RCA VIP and many other
single board computers that use the 6502, 6800, 8080/85, Z-80, 1802,
F-8 and 2650 CPU's. Stock. Specify one set of software.

Optimal Technology Inc. ^ 29

Blue Wood 127
Earlysville, VA 22936 U.S.A.

Phone (804) 973-5482

/T

APPLE 11 PLUS WITH 48K RAM
TEXAS INSTRUMENT 99/4 COMPUTER
TI8I0 PRINTER
CENTRONIC PRINTERS:

730-1 PARALLEL PRINTER
737-1 PARALLEL INTERFACE
SAVE ON ALL OTHER MODELS
SPINWRITERS FROM NEC
55 10 R/O SERIAL INTERFACE
5520 KSR SERIAL WITH KEYBOARD
5530 PARALLEL INTERFACE
PAPER TIGER 440
440G

BASE-2 PRINTERS
800M.S.T.

COMPRINT 912 APPLE, TRS-80, PET
912 SERIAL
SYM-I W/MANUALS
COMMODORE BUSINESS MACHINES:

CBM 8016
8032

PET 2001 -8K COMPUTER
PET2001-16K
PET2001-32K

PET 2022 TRAC. FEED PRINTER
PET 2023 FRIC. FEED PRINTER
PET 2040 DUAL FLOPPY DISK DRIVE
PET 8050
ATARI 800

INTERTEC SUPERBRAIN (32K)

NORTH STAR COMPUTERS
H RZ-2-32K-D- ASM
H RZ-2-32K-Q- ASM
DISPLAY TERMINALS:

INTERTUBE II
HAZELTINE 1410
HAZELT1NE 1420
SAVE ON COMPLETE HAZELTINE LINE
IMMEDIATE DELIVERY FROM STOCK PRICES SUBJECT TO CHANGE
MULTI-BUSINESS COMPUTER SYSTEMS

28 MARLBOROUGH STREET ^ 81
PORTLAND, CONN. 06480

$1190.
$ 989.
$1590.

$ 659.
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$2490.
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M/F 9-6 SAT 9-3 (203) 342-2747

IH

TWK: 710-428-6345
MBCSYS

WS4 i J

""I

134 Microcomputing, October 1980

SIRIUS 80+

Perfect Add-Ons for Your
Computer System!

PRIAM

Hard Disks
Now Available
from SIRIUS
SYSTEMS!

PRIAM's high-performance, low-cost Winchester disc drives speed up throughput and expand data storage
from 20 megabytes to 154 megabytes. And a single controller can be used to operate 14-inch-disc drives with
capacities of 33, 66, or 154 megabytes or floppy-disc-size drives holding 20 and 34 megabytes. So it’s easy to
move up in capacity, or reduce package size, without changing important system elements or performance.

I Fast, Linear Voice Coil Positioning
I 10 ms track-to-track positioning
I Fully servoed head positioning
I Dedicated servo tracks

I DC Power required only!
I Simple, parallel Interlace
I Optional SMD Interface

I 50 ms Average Positioning time
I 90 ms Maximum Positioning Time
I 6.4 ms Average Latency

Model/Disc Size

DISKOS 3350
DISKOS 6650
DISKOS 15450 (14"
DISKOS 2050
DISKOS 3450
DISKOS 570
DISKOS 1070

THE PRIAM LINEUP

Size

7" x 17" x 20"

7" x 17” x 20"

7" x 17" x 20"
4.62” x 8.55” x 14.25"
4.62" x 8.55" x 14.25”
floppy-size
floppy-size

Weight Price

33 lbs. $2995

33 lbs. $3749

33 lbs. $4695

20 lbs. $2995

20 IbS. $3745

(low) (low)

(low) (low)

Capacity

33Mbytes
66 Mbytes
154 Mbytes
20 Mbytes
34 Mbytes
5.3 Mbytes
10.6 Mbytes

All PRIAM DISKOS Drives have a Transfer Rate of 1 .03 Mbytes/Sec.

Optional SMD interface available for $150.

SIRIUS SYTEMS offer cases and enclosures for all PRIAM Hard Disk Drives. All 14" Winchester
Drives will mount in our 14" Standard Case. The 8" Winchesters have two alternatives: a single
drive case and a dual drive case. All SIRIUS SYSTEMS Winchester drive cases include Power
Supply, internal cabling, switches, fan, extra AC outlet (not switched, but fused) and possess very
adequate ventilation. Drive addressing is done on the rear of the Case and not on the drive iteself
to provide ease of use during operation. All WINCHESTER DRIVE Cases are Warranted for a full
year and come in our standard blue-black color scheme. Consult us for current availability and
pricing.

Remex rfd 4000/4001
8" Floppy Disc Drives
Double sided . . .

Double density!!

*549

95

RFO 4001 ,$569.95

Offers quality and features found in drives costing much
more! ■ Single or Double Density ■ Double-Sided Drive ■ Door Lock INCLUDED
■ Write-Protect INCLUDED ■ 180 Day Warranty ■ Compatible with Shugart
850/851 ■ Low Power Operation ensures LONGER LIFE!! ■ Model RFD 4001 offers
Data and Sector Separator
RFD 4000/4001 Technical Manual 6.95

Connector Set #3 (AC, DC, Card Edge) . 1 0.95 RFD 4000C/B Cabinet (for use with
Connector Set #4 (AC and DC) 2.95 Power Modules) 29.95

Remex lOOOB . . . If you've been looking — ~

for a less expensive floppy disc drive,
but not wanting to sacrifice quality —
this Is It!

$41995

You get both in the Remex 1000B! For only $419.95 look
at what you get: ■ 8" Floppy Drive ■ Single or Double Density
■ Hard or Soft Sectoring* Media Protection Feature ■ Single Density
Data Separator ■ 180 Day Factory Warranty

Door Lock Option $19.95 Write Protect Option .

Interface Adapter Connector Set # 1

(REMEX-to-Shugart) . . $14.95 (AC, DC, & Card Edge).

$19.95 RFD 1000B Technical Manual $5.95
RFD 1000B CASE (for use
$10.95 (with Power Modules) $29.95

SIRIUS 8" DISK
POWER MODULES

The Single and Dual Drive Power Modules are
designed to provide DC and (switched) AC
power for one (the Single Drive Power Mod-
ule) or two (the Dual Drive Power Module—
the DDPM will power three RFD 4000s or
4001s) 8” Floppy Disk Drives. Many features
are included for safe and reliable operation
and the Power Modules come with our stan-

dard 180 day WARRANTY (the Open Frame
Power Supply warranty is tor 2 years). All
Power Modules will work with either the RFD
4000C/B or RFD 1000B case (color schemes
match also).

Dual Drive

Power Module (DDPM) $139.95

Single Drive

Power Module (SDPM) 119.95

The SIRIUS SYSTEMS 80+ Series of Floppy
Disk add-ons are designed to provide un-
matched versatility and performance for your
computer. Consisting of four different add-ons,
there is a 80 + Series Floppy Disk to meet your
need. All 80+ Series Floppy Disk are compatible
with the TRS-80* and come ready to plug in!

COMMON CHARACTERISTICS

■ 5 ms track-to-track access time
m Auto-eject

■ 180 day WARRANTY

■ Exceptional speed stability — V/ 2 %

U Sinple density (FM) or double density (MFMI

m Ultra high reliability

■ 2 year Power Supply Warranty

■ Mix any or all 80 + Series on the same cable!

■ Includes user accessible plugboard for drive
reconfiguring

SPECIFIC CHARACTERISTICS
The SIRIUS 80+1 is a single sided, 40 track,
highly reliable Floppy Disk add-on. Offering 5
more tracks than the Radio Shack model, it cost
$140 less! Formatted data storage is 102K/20K
bytes single/double density.

SIRIUS 80+1 $359.95

The SIRIUS 80+2 is a dual sided, 70 track (35
per side), highly versatile Floppy Disk unit. It
appears to the TRS-80* as TWO 35 track drives,
yet COST LESS THAN HALF THE PRICE! Even
reater savings result, since data is recorded on
oth sides of the media instead of only a single
side. Using the plug board, it may be recon-
figured for other computer systems! (The 80+2
operates as Drive 0 and any of the other three
addresses (with the sandard Radio Shack Cable)
or as any of four drives (with the SS Standad
Cable).! Formatted data storage is 80.6K/
161 ,2K bytes single/double density.

SIRIUS 80+2 $449.95

The SIRIUS 80+3 is a single sided, 80 track,
"Quad” density Floppy Disk unit. Offering 2!ft
times the storage of a Standard Radio Shack
drive, the 80-r3 greatly reduces the need for
diskettes correspondingly. Additionally,
because of the increased storage and faster
track-to-track access time, the 80+3 allows tre-
mendously increased throughput for disk based
programs!!! The 80+3 INCLUDES SIRIUS’s
TRAKS-PATCH on Diskette. Formatted data
storage is 204K/40K8 bytes single/double
density.

SIRIUS 80+3 $489.95

The SIRIUS 80+4 Floppy Disk add-on is a
double sided, 160 track (80 per side), 5V4"
monster! The ultimate in state-of-the-art 5V4"
Floppy Disk technology, to 80+4 is seen by the
TRS-80* as two single sided disk drives, each
with 80 tracks. Thus, in terms of capacity one
80+4 is equivalent to 4% standard Radio Shack
drives — a savings of over 73% (not to mention
diskettes!!!). (With a double density converter,
the available memory is huge!) The 80+4 is
similar to the 80+2 in that it arrives configured
as Drive 0 and any of the other three addresses
(with the standard Radio Shack Cable) or as any
of four drives (with the SS Standard Cable) The
80+4 INCLUDES TRAKS-PATCH on Diskette.
(The plug board is also included.) Formatted
data storage is 408K single density or 816K
bytes double density.

SIRIUS 80+4 $624.95

0

All 80+ Series Floppy Disk add-ons operate a 5
milliseconds track-to-track access time (eight
times faster than the SA 400) but are Expansion
Interface Limited to 12 milli-seconds for the
TRS-80*.

*TRS-80© Tandy Corp.

SIRIUS
SYSTEMS

7528 Oak Ridge Highway
Knoxville, Tennessee 37921 ^67

TO ORDER CALL (615) 693-6583

Phone Orders Accepted 9AM-7PM (ESDT)

We accept MC, VISA, AE, COD (requires Certified Check, Cashier’s Check
or Cash) and Checks (personal checks require 14 days to clear). SHIPPING
AND HANDLING: $7.00 per Floppy Disk Drive or 80+ Module ■ 5% for other
items (any excess will be refunded) ■ Foreign Orders add 10% for Shipping
& Handling. Payment in U.S. currency ■ Tennessee residents add 6% Sales
Tax ■ VOLUME DISCOUNTS AVAILABLE

MPI 51/52 . . .

A Great Reliable Mini-Drivel

■ Fast! 5ms track to track access

■ Exclusive Pulley-Band Design

■ Unique Door/ Ejector Mechanism
m Reliable V/ 2 % Speed Stability

m Single/ Double Density Operation

■ Industry/ ANSI Standard Interface

(Single Head, 40 tracks, 120K/240K
bytes Single/Double Density**)

MPI 52

(Dual Head, 70 tracks, (35/side),
218.8K/437.5K Single/Double Den-
sity**)

$259.95

$349.95

MPI 91/92... NEW

STATE-OF-THE-ART

DISKDRIVE!

MPI 91

(Single Head, 80 tracks. 240K/480K
Single/Double Density**)

MPI 92

(Single Head, 160 tracks (80/side),
480K/960K Single/Double Den-
sity**) ....

** Unfomnatb.

latteddata storage

$389.95

$499.95

introducing the
Versatile, Low-Cost
OMEGA Series
Controller

As new technological advances bring down the
cost of fast, reliable mass data storage, the need
for an inexpensive, versatile controller have be-
come greater and greater. To meet this need,
SIRIUS SYSTEMS’ OMEGA Series Controller
was designed.

The SIRIUS OMEGA Series Controller Module
utilizes an on-board microprocessor to
mediate data transfer to a. wide variety of
peripherals from an equally wide variety of host
computer systems. Up to four Winchester Hard
Disks (8” or 14"), four5V4” Floppy Disks Drives
and/or up to eight 8” Floppy Disk Drives may be
in use at one time. Host systems interfacing
is accomplished via a parallel or a serial inter-
face. With the additon of a Personality module,
the OMEGA Series Controller Module is directly
compatible with many popular com-
puter systems (among them the TRS-80*.
Apple, Heath, and others). Provision is made for
the addition of a streaming tape drive, also.

SPECIFIC HARDWARE
FEATURES INCLUDE:

■ Control of up to twelve Floppy Disk Drives
(eight 8" and/or four5V *")

• 8 '' and/or 5% ” Disk Drive Utilization

• Single (FM) or Double (MFM) density data
storage

• Hard or Soft sectored diskette usage

• Utilization of “Quad" density (96 tpi) 8" or
5 ^/ 4 ” Disk Drives

■ Control of up to four WINCHESTER type
PRIAM DISKOS Disk Drives

• 8" or 14" may intermix on the same cable

• Accommodates 8" andlor 14” drives of
5.3Mbytes to 154Mbytes

• Ultra-Fast data transfers

■ Extremely flexible host-controller interfacing

SPECIFIC SOFTWARE
FEATURES INCLUDE:

■ Dynamic format modifications via command
words

■ Extremely flexible format acceptance for un-
usual data storage formats

■ Easily interfaces to standard operating sys-
tems (TRS-DOS*, CP/M***, etc)

■ Operates in either get/put sector mode or
data string mode

■ Performance parameters may be changed by
EPROM replacement or Dynaminic Repro-
gramming

Dedicated systems cards are also available on a
limited basis for the STD-BUS and the S 100.
These cards feature shared memory also (again,
software selectable) in addition to the regular
OMEGA Series Controller Module features. Con-
sult SIRIUS SYTEMS for current price and
availability for the entire line of OMEGA Senes
Memory Units and Controllers. Dealer inquir-
ies are invited.

iS Reader Service index— page 241

Microcomputing, October 1980 135

Low Overhead Cassette Format
For 6800 Systems

No longer do you have to suffer the inconvenience
of using 300 baud Kansas City Standard.

Dr. Gordon W. Wolfe
Department of Physics
The University of Mississippi
University , MS 38677

O wners of cassette-based 6800 micro-
computers such as the SWTP 6800
have for years put up with the slow loading
and punching process known as the Kan-
sas City Standard and the MIKBUG
cassette format. The Kansas City Standard
is akin to a frequency-shift encoding, but
uses an eight-fold redundancy to assure
proper character recognition. This eight-
fold redundancy results in character rates

of only 300 baud.

But the MIKBUG format is the real culprit
in most 6800-based systems. MIKBUG was
one of the first, and certainly the most suc-
cessful, of the 6800 operating systems, and
manufacturers of other operating systems
these days take pains to remain MIKBUG-
compatible. Such operating systems as
SWTBUG, SMARTBUG and RT-68/MX all
have the same I/O routines in the same loca-
tions, and all use the same tape punch for-
mat.

This has virtually locked the 6800 user in-
to this format (Fig. 1). To output 16 bytes of
data to tape, there is a “start of
record”— the characters SI. Next comes
the count of the number of bytes to follow.

And here is where MIKBUG slows down.

Nineteen (decimal) bytes will follow, so
the computer punches that 13 (hex) bytes
follow— but it punches a one and a three in
ASCII. That is, for this and all succeeding
bytes, it punches two characters. Following
the count, there is the start address of the
record (two bytes; four characters), and
then 16 bytes of data (32 characters) and a
checksum (two characters). Also, at the end
there is a carriage return and line feed.

Total It up: to punch, or record on
cassette, only 16 bytes, MIKBUG must out-
put a total of 44 characters, or 2.75
characters for every byte of data. This is
very wasteful overhead. If this overhead
could be removed, cassette loading time (or
TTY loading from paper tape) could be
speeded up by a factor of 2.75.

Some suggested remedies, such as in-
creasing the record length from 16 to 256
characters, or outputting a pseudo-binary
(with the parity bit, bit 7, set to zero) record,
have not completely succeeded. The best
solution is to simply output straight binary
data with as little overhead as possible.

Fig. 2 shows a scheme this author has
used successfully. As in MIKBUG, an SI is
used as a start-of-record. Anything that oc-
curs on the tape before this SI is ignored.
Then follows the start address for the
record (four ASCII characters representing
two bytes) and a space. Then follows, byte
for byte, one character for one byte in the
same order as in memory. Any number of
bytes are punched— one byte, up to all of
memory. When data is finished, an end-of
record “S9R” is punched.

The Program BIPNCH

An assembly-language program named
BIPNCH has been written to take care of

SI I3I00044E923CI 5B

Fig. 1. MIKBUG punch format.

Fig. 2. BIPNCH punch format.

136 Microcomputing, October 1980

BPUNCH

$7F00

Punch subroutine

DONE9

$7F1D

Subroutine prints end of record

SECDEL

$7F51

Subroutine delays one second

TLOOP

$7F53

Subroutine delays a number of
half-seconds equal to ACCB

BILOAD

$7F62

$7F9E

Load subroutine

Reset MP-C PIA FOR ECHO

Table 1.

(MIKBUG Monitor)

* M A048
A048 DF 7F
A049 13 2A
A04A 22
*G

10100 01FF (punches $0100-$01FF)

Sample Run 1.

data loading and punching in this binary
format, and is shown in Program 1. The pro-
gram was written for use on an SWTP 6800
micro using RT68/MX as an operating
system. It presumes memory at $A000, and
that an MP-C control interface at $8004 is
used for communication to the terminal.
However, as will be shown later, the pro-
gram may be easily modified to other
systems.

BIPNCH is an example of structured pro-
gramming; that is, it is written as two
monitor-called routines, and a series of
subroutines.

The punch routine, BOUT, is called from
the monitor by executing location $7F2A.
The program outputs a prompt (!) and waits
for the user to input the start and end ad-
dresses of the region to be punched. When
this is done, the program calls the punch
subroutine to output headers, data and end-
of-record, and returns to the monitor. Sam-
ple run 1 shows how it works.

The loading routine, BIN, is called from
the monitor by executing location $7FAB.
The program disables the MP-C echo and
loads the data automatically, returning to
the monitor when done.

Both routines will, of course,
automatically start and stop the recorder if
used with an AC-30 interface.

It should be noted that the punch routine,
if used with a terminal and AC-30 interface,
will cause characters to print on the screen.
Control characters will cause controlled
devices to actuate (including recorder
on/off), so it is recommended that the con-
trol functions be deactuated when punch-
ing. On the CT-1024 terminal by SWTP, this
may be done by adding a switch that
disconnects pin 3 of IC8 on the CT-CA cur-
sor control board. There is no difficulty dur-
ing the read routine, since the echo is
disabled.

NAM BIPNCH

*

E07E

PDfiTfil EQU

IE07E

E0CC

OUTS EQU

$E0CC

E0C8

0UT4HS EQU

IE0C8

E04?

BfiDDR EQU

$E047

E1D1

OUTEEE EQU

$E1D1

8016

ST8DR EQU

$8616

8014

ENflDR EQU

$8614

E0E3

C0NTL EQU

IE6E3

♦INPUT ROUTINE DOES
♦NOT STRIP PfiRITV BIT

E359

INEEE EQU
*

$E359

7F00

ORG

*

$7F60

♦PUNCH SUBROUTINE

7F00

CE

7F

B0

BPUNCH LDX

I0PHDR

7F03

BD

E8

7E

JSR

PDfiTfil

7F06

CE

fie

16

LDX

♦STADR

7F09

BD

E8

C8

JSR

0UT4HS

7F0C

FE

m

16

LDX

STADR

7F0F

fib

00

M0RE1 LDfifi

0/ X

7F11

BD

El

D1

JSR

OUTEEE

7F14

BC

80

14

CPX

ENfiDR

7F17

27

03

BEQ

D0NE1

7F19

08

I NX

7F1H

28

F3

BRfi

M0RE1

7F1C

39

D0NE1 RTS
*

♦END OF RECORD

7F1D

CE

7F

B3

D0NE9 LDX

IESS9

7F26

BD

E0

7E

JSR

PDfiTfil

7F23

8D

2C

BSR

SECDEL

7F25

86

14

LDflfi #$14

7F27

7E

El

D1

JMP

jit

OUTEEE

♦MONITOR CALL FOR
♦PUNCH ROUTINE

7F28

CE

7F

67

BOUT LDX

♦PROMPT

7F2D

BD

E0

7E

JSR

PDfiTfil

7F36

BD

E0

47

JSR

BfiDDR

7F33

FF

88

16

STX

ST8DR

7F36

BD

E6

CC

JSR

OUTS

7F39

BD

E8

47

JSR

BfiDDR

7FX

FF

86

14

STX

ENADR

7F3F

8D

10

BSR

SECDEL

7F41

8b

12

LDfifi

#$12

7F43

BD

El

D1

JSR

OUTEEE

7F46

8D

09

BSR

SECDEL

7F48

8D

B6

BSR

BPUNCH

7F48

80

B1

BSR

DONES

7F4C

SD

03

BSR

SECDEL

7F4E

7E

E0

E3

JMP

*

CONTL

♦SUBROUTINE
♦ONE SECOND

DELAYS

7F51

C6

02

SECDEL LDfiB

#2

♦HALF SEC0N;

) DELAY

*8T TLOOP IF B=i

7F53

CE

F4

FF

TLOOP LDX

#$F4FF

7F56

09

DECX DEX

7F57

26

FD

BNE

DECX

7F59

58

DECB

7F5R

26

F7

BNE

TLOOP

7F5C

39

RTS

*

♦MONITOR CALL TO
♦OUTPUT "S9R" DfiTfi END

7F5D

80

BE

S9 BSR

D0NE9

7F5F

7E

EB

E3

JMP

*

CONTL

♦SUBROUTINE FOR
♦BINARY DATA IN

7F62

CE

7F

BB

BIL0AD LDX

#RD0N

♦SET PIA NO

ECHO

7F65

C6

3C

LDfiB

#$3C

7F67

F7

80

07

STAB

$8067

7F68

BD

E0

7E

JSR

PDfiTfil

♦INPUT DATA

HEfiDER

7F6D

BD

E3

59

AGAIN JSR

INEEE

7F70

81

53

CMPA

#'S

7F72

26

F9

BNE

fiGAIN

7F74

80

E3

59

JSR

INEEE

7F77

81

31

CMPfi

#'l

7F79

26

F2

BNE

AGAIN

7F7B

BD

E0

47

JSR

BfiDDR

In addition to the two monitor call
routines listed above, there are user-
accessible subroutines which may be of
value in other programs. They include the
punch and load subroutines themselves. In
MIKBUG, the user must go to the monitor to
write to or read from tape, or write his or her
own routines. Here, the routines are usable
directly. To punch, load the start and end
addresses to punch into $A016 and $A014,
respectively, and jump to the subroutine at
$7F00. To load, or read a tape, jump to the
subroutine at $7F62. Table 1 is a list of
subroutines, their locations and what they
do. Note that a monitor-callable program

7F7E

BD

E3 59

JSR

INEEE

7F81

81

28

CMPfi

#$26

7F83

26

E8

BNE

AGAIN

♦DfiTfi

INPUT

7F85

8D

ID

M0RE2

BSR:

INPUT

7F87

81

53

CMPfi

#'S

7F89

26

Ffl

BNE

M0RE2

7F8B

SC-

17

BSR

INPUT

7F8D

SI

39

CMPfi

#'9

7F8F

26

F4

BNE

M0RE2

7F91

8D

11

BSR

INPUT

7F93

81

52

CMPA

i'R

7F95

26

EE

BNE

M0RE2

7F97

8D

B8

BSR

SECDEL

7F99

86

13

LDAfi

#$13

7F9B

BD

El D1

JSR

OUTEEE

♦PIfl RESET

7F9E

C6

34

LDAB

#$34

7Ffi0

F7

80 07

STAB

$8067

7Ffi3

39

RTS

7Ffi4

BD

E3 59

INPUT

JSR

INEEE

7Ffi7

fl7

00

STAR

0,X

7F89

08

I NX

TFfiA

39

*

RTS

♦MONITOR CALL FOR

♦BINARY DfiTfi INPUT

7F8B

8D

B5

BIN

BSR

B I LOAD

7F8D

7F

E0 E3

JMP

C0f4TL

7FB0

53

OPHDR

FCC

'Si'

7FB1

31

7FB2

04

fcb

4

7FB3

53

ESS9

FCC

'S9R'

7FB4

39

52

7FB6

04

FCB

4

7FB7

0D

PROMPT

fcb

$D, $fi, J

7FB8

0fl

21

TFBfi

04

7FBB

11

RD0N

FCB

$11, $4

7FBC

04

*

EM)

NO ERR6RCS) DETECTED

SYMBOL TABLE.

AGAIN

7F6D

BADDR

E047

BILOfiD

7F62

BIN

7FAB

BOUT

7F2A

BPUNCH

7F80

CONTL

E0E3

DECX

7F56

D0NE1

7F1C

D0NE9

7F1D

ENflDR

A014

ESS9

7FB3

INEEE

E359

INPUT

7FA4

MOREi

7F0F

M0RE2

7F85

OPfOR

7FB8

0UT4HS

E0C8

OUTEEE

E1D1

OUTS

E0CC

PDfllfil

E07E

PROMPT

7FB?

RDON

7FBB

S9

7F5D

SECDEL

7F51

STADR

A01b

TLOOP

7F53

Program 1.

Microcomputing, October 1980 137

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COMMODORE PET Call for Prices

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ersonal
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is 303

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(315) 478-6800

PDATA 1

$E07E

Output data string terminated by
EOT

OUTS

$E0CC

Output a space

OUT4HS

$E0C8

Output 2 bytes in ASCII hex,
with a space

BADDR

$E047

Input 2 bytes in ASCII hex

OUTEEE

SE1D1

Output a character from ACCA

CONTL

$E0E3

Jump to monitor

Table 2.

places “S9R” at the end of a tape; this is
useful even with MIKBUG.

How Does It Work?

In a word, magnificently. Instead of 22
minutes to load 8K BASIC, it now requires
only eight minutes. It is possible to double
the amount of work I get out of my machine.

The program fits very nicely into a 256 x
8 1702A EPROM at $7F00, with con-
siderable room left over for other routines.
Only four bytes of RAM are used at
$A014-$A017, and the code is not self-
modifying, so that it may be placed in
EPROM.

Modifications to Other Systems

As stated above, the program may be
easily modified for other 6800 systems.

If you desire to place the program into a
location other the $7F00, you may reassem-
ble it to any other location, or modify the ad-
dresses of the instructions at $7F00, $7F1 D,
$7F2A and $7F62.

Virtually all the external routines in
BIPNCH are MIKBUG-compatible. Table 2
lists these routines, and what they do.
There should be no trouble with MIKBUG,
SWTBUG, SMARTBUG or RT-68/MX.

If you are using an ACIA, rather than an
MP-C control interface, the PIA echo/no
echo routines at $7F65 and $7F9E must be
rewritten.

The only critical external routine which
will require extensive modification is the
character input routine. It was discovered
that both MIKBUG and RT-68/MX strip the
most significant bit (set bit 7 equal to zero)
whenever a character is input via the
subroutine INEEE at $E1AC. Naturally, this
is unacceptable, because when you save
programs, approximately half the instruc-
tion bytes will have bit 7 equal to 1.

In RT-68/MX, the solution is simple. Enter
the subroutine at $E359, after the parity bit
stripping function. Then the character is in-
put exactly as recorded. For MIKBUG and
SMARTBUG, however, the solution is not so
simple. It is not possible to bypass the pari-
ty stripping so simply. I have no information
on SWTBUG, but I presume it is similar.

For those who use these other monitors,
Program 2 shows an input routine for MP-C
interface which does not strip the parity bit.
It is ORGed at $E359, but is relocatable to

pm

NAM INEEE2

*

♦MP-C INPUT ROUTINE
♦DOESN'T STRIP PflRITV
♦RELOCATABLE
♦NON-REENTRANT
♦INPUTS CHftR TO ACCA
♦FROM MP-C AT $8664
♦

XTEMP EQU $8016

E359

ORG $£359

8

UJ

37

*

PSHB

E35R

FF fiO 10

STX XTEMP

E35D

CE 86 04

LDX #$8664

£

E360

fl6 00

♦WAIT FOR STftRT BIT
♦AND STftRT TIMER
PIA LDftft 6,X

E362

20 FC

BMI PIfi

E364

6F 02

CLR 2/X

E366

8D 22

BSR BIT

E368

8D 1C

BSR WAIT

E36fi

C6 64

LDAB #4

E36C

E7 02

STftB 2/ X

*

E36E

58

♦INPUT 8 BITS
ftSLB

E36F

SD 15

PIA2 BSR WRIT

E371

0D

SEC

E372

69 06

R0L 0/ X

E374

46

RORfi

E375

5R

DECB

E376

26 F?

BNE PIA2

E378

80 0C'

BSR WRIT

*

E37A

EG 02

♦TEST # STOP BITS
CHECK LDAB 2, X

E37C

58

ftSLB

E37D

2A 62

BPL RES

E37F

8D 05

BSR WAIT

*

E381

FE R0 16

♦RETURN

RES LDX XTEMP

E3o4

33

PULB

E385

39

RTS

£

E3S6

60 02

♦TIMERS

WAIT TST 2/X

E388

2ft FC

BPL WAIT

E38R

6C 02

BIT INC 2j X

E3SC

6ft 82

DEC 2/X

E38E

39

RTS

*

END

NO ERR0RCS) DETECTED

SVM6UL TROLL

BIT

E38A

CHECK E37A

PIA

E360

PIR2 E36F

RES

E381

WAIT E386

XTEMP

R010

Program 2.

any other location. I must emphasize that
this is similar to, but not the same way as it
is done in RT-68/MX, to avoid copyright vio-
lations.

Last, there are some difficulties with
using the binary loading technique. I have
pointed out the control character problem
above. Just as serious is the lack of
checksum. The program has no way of
knowing if there were any loading errors.

I must say, though, that In eight months
of using the program, I have never had a bad
load. Even if I did, it only takes a few
minutes to re-load. U

138 Microcomputing, October 1980

FROM PROGRAMMA

HI-RESOLUTION GRAPHICS FOR THE TRS-80*

The 80-GRAFIX board includes
two sets of lower case characters
at no additional cost.

DEMONSTRATION PROGRAMS

The 80-GRAFIX board is supplied
with a Character Generator software
and several demonstration programs.

FINALLY, AT LAST. . .

HI- RESOLUTION GRAPHICS is available for your
TRS-80 computer system. The 80-GRAFIX board from
PROGRAMMA International, Inc. gives your TRS-80 high
resolution capability that is greater than the Commodore
CBM/PET or even the revered APPLE II.

80-GRAFIX gives the TRS-80 an effective screen of
384X192 pixels, versus the normal 127X192 for the
TRS-80, 80X50 for the CBM/PET, or the 280X192 of an
APPLE II. As an added feature, 80-GRAFIX offers you
lower case characters at no additional cost. Of course, you
can also create your own set of up to 64 original characters
using the supplied Character Generator software.

The 80-GRAFIX board is simple to install (note that this
voids your Radio Shack warranty), and programming is
done through BASIC. 80-GRAFIX opens up a whole new
realm of software development and excitement never
dreamed of for the TRS-80!

INVERSE VIDEO

The 80-GRAFIX board allows you to

do inverse video to high light your
screen displays.

CHARACTER GENERATOR

The supplied character generator
software allows you to create your
own character set of up to
64 original characters.

REAL-TIME GRAPHIC GAMES

With the 80-GRAFIX board you can
write exciting real-time games using
BASIC.

EASY INSTALLATION

The 80-GRAFIX board is simple to
install and fits inside the TRS-80 case.

r T 7*1 4 I 5 » ‘1 7 1 *1

CH«nnsr... ^

♦ IJIJU 1

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ir ]

(OWIK AOHKT!) I

5| ‘| WJSBTM

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mi mnat

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<9ftW TO )!2

(STxr mo

GRAPHICS GALORE

The 80-GRAFIX board and
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allow you to become an artist.

ELECTRONIC DESIGN

The 80-GRAFIX board has unlimited
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80 GRAFIX HI-RESOLUTION

Finally, the only means t6 protect
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(213) 384-0579 • 384-1116 • 384-1117

\S Reader Service index— page 241

Microcomputing, October 1980 139

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This program allows reliable high speed file transfers between two
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With this program you will no longer need to convert machine
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PROGRAM INDEX FOR DISK BASIC

Assemble an alphabetized index of your entire program library
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Finally, the list itself may be stored on disk for future access and
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SINGLE STEP THROUGH RAM OR ROM

STEP80 allows you to step through any Basic or machine lan-
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count for each instruction. The top 14 lines of the video screen are
left unaltered so that the “target program” may perform its display
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the ROMs, and is an invaluable aid in learning how the ROM
routines function. Commands include step (trace), disassemble,
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•All programs require 16K • TRS 90 programs require Level II BASIC • Apple programs require Applesoft BASIC.
m 124

Send check or money order to Krell Software S©
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140 Microcomputing, October 1980

SPECIAL PRICES

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Reader Service index— page 241

Microcomputing, October 1980 141

Exploring CT-82 Graphics

The author leads you on an expedition
to uncover the capabilities of this SWTP video terminal.

” ■

1 1 — 1

Photo 1. CT-82 from the outside.

CLEAR GRAPHICS DOT— Turn off a pixel at the specified position.

INVERT GRAPHICS DOT— Invert a pixel at the specified graphics position.

SET GRAPHICS DOT— Turn on a pixel at the specified graphics position.

CLEAR GRAPHICS LINE— Clear the straight line between two specified points.

INVERT GRAPHICS LINE— Invert a straight line between two points, i.e., turn off each point that is on and turn on
each point that is off.

SET GRAPHICS LINE— Draw a straight line between two points.

PITCH DOWN GRAPHICS SCREEN— Roll the pixels on the screen downward one pixel position.

PITCH UP GRAPHICS SCREEN— Roll the pixels on the screen upward by one pixel position.

YAW LEFT GRAPHICS SCREEN— Shift the pixels on the screen left by one pixel position.

YAW RIGHT GRAPHICS SCREEN— Shift the pixels on the screen right by one pixel position

Fig. 1. CT-82 graphics commands. (Note: A pixel is a picture element, the smallest ad-
dressable piece of data on the graphics screen.)

Phil Hughes
PO Box 2847
Olympia, WA 98507

T he CT-82 is a video terminal by South-
west Technical Products Corporation
(see Photo 1). Internally, it is based on a
6802 microprocessor and a Motorola 6845
CRT controller 1C (see Photo 2). In its normal
mode, it can display either 16 or 20 lines of
82 alphanumeric characters each and sup-
port scrolling (when the last line on the
screen is filled, all lines are rolled up to
allow space for a new line). It features other
capabilities not found in “dumb” terminals.

Additionally, the CT-82 supports graph-
ics commands that allow you to draw and
manipulate dots and lines on the screen.
Each of these capabilities is exercised by
sending a specific control sequence from
the computer to the CT-82. Figure 1 lists the
graphics commands supported by the
CT-82.

142 Microcomputing, October 1980

TEST82

To get the feel of the graphics capabili-
ties, I wrote an assembly-language pro-
gram, TEST82 (see Listing 1), which allows
me to use the set and clear commands for
both dots and lines. This program sends the
required sequence to put the CT-82 into its
graphics mode and then prompts for a com-
mand. Figure 2 lists the commands
recognized by TEST82. The display il-
lustrated in Photo 3 was created by execut-
ing TEST82 and entering the following com-
mands:

DL 0 0 183 0 Top line
DL 0 62 183 62 Bottom line
DL 0 0 0 62 Left side

DL 183 0 183 62 Right side
DL 20 0 60 60 Create
DL 60 0 20 60 X

Note that all of the assembly-language
routines in this article were written using
RRMAC from Ed Smith’s Software Works.
Also, they all reference an “include” file for
Flex Interface addresses. (Flex is a disk op-
erating system for the 6800 by Technical
Systems Consultants.) Listing 2 is a dummy
program that references the include file.
This shows all the Flex entry equates and
their values.

Internally, TEST82 is easy to follow.
When initially entered (at label START), the
CT-82 is put in the graphics mode by send-
ing it the string SMSG. Scrolling is also dis-
abled so that entering a carriage return on
the command line (bottom line of the
screen) will not cause the display to scroll
up one line. The code starting at the label
NEXTCMD gets a line of user input using
the Flex subroutine INBUFF, saves the first
input character in accumulator B, saves the
second input character in accumulator A
and then skips the spaces that should fol-
low the commands.

The command is then analyzed, and con-
trol is passed to the appropriate rou-
tine— EXIT for the X command, CLEAR for
the CS command, DRAW for the D com-
mand and ERASE for the E command. If the
command is not valid, routine INPERR is-
sues an error message, waits for a carriage
return and then returns to the NEXTCMD

cs

x

DP XI Y1
EP XI Y1
DL XI Y1 X2 Y2
EL XI Y1 X2 Y2

Clear screen
Exit

Draw point
Erase point
Draw line
Erase line

Note: the screen is composed of 184 vertical columns
of 66 pixels each. These pixels are numbered 0-183
from left to right and 0-65 from top to bottom. The X
value in each command is the column number and the
Y value is the row number. Rows 63 through 65 are not
available as they are used as the command entry line.

Fig. 2. TEST82 commands.

Photo 2. Inside view of the CT-82.

Listing 1. TEST82.

2

3

4

138

139

140

141

142

143

144

145

146

147

148

149

150
1 51
152

3R
12 i
3R
12 i
21 *

30 *
34
3R
2R

11 *
15

0000

0000

0000
El D1
0000

0000 CE 00EB
0003 BD AD 1 E
0006 CE 00F2
0009 BD ADI E
000C BD AD 1 B

NAM TEST82
OPT X R F , PNT

CT82 GRAPHICS TEST PROGRAM
SSC 8-2-79 VI. 14

OPT PNT

0UTEEE

START

000 F BD
0012 24
0014 7E

0017 16

0018 BD
00 1 B 36

A D 2 7

03 (0017)
0040

EQU

EQU

LDX

JSR

LDX

JSR

JSR

JSR
BCC
J MP
TAB
JSR
PSH

X'EIDI '

# SMSG

PSTRNG

^PROMPT

PSTRNG

INBUFF

NXTCH

$ 5

INPERR

USED FOR SPECIAL CHARAC
TERS

GET INPUT INTO LINE BUF
FER

GET FIRST CHAR

GET POSSIBLE L OR P
SAVE

154

28

001 F

32

PUL

A

155

30

0020

Cl

43

CMP

B

K'C

CLEAR?

156

34

0022

26

07 (002B)

BNE

$8

157

2 R

0024

81

53

CMP

A

UZ' S'

CS - CLEAR SCREEN ?

158

6

0026

26

03 (002B)

BNE

S8

159

3R

0028

7 E

00B3

J MP

CLEAR

160

2 R

002B

Cl

44

S8

CMP

B

KC'D'

DRAW?

161

6

00 2D

26

03 (0032)

BNE

sio

NO

162

3 R

002 F

7 E

0055

J MP

DRAW

163

2 R

0032

Cl

45

S10

CMP

B

n C’E'

ERASE?

164

6

0034

26

03 (0039)

BNE

$12

NO

165

3R

0036

7 E

0084

J MP

ERASE

166

2 R

0039

Cl

58

S 1 2

CMP

B

#C ' X '

EXIT?

167

6

00 3B

26

03 (0040)

BNE

INPERR

168

3R

003D

7E

004 C

J MP

EXIT

169

3R

0040

CE

00FF

INPERR

LDX

# I E MSG

1 70

12 *

0043

BO

ADI E

JSR

PSTRNG

ERROR MESSAGE

171

21 *

0046

BD

ADI B

JSR

INBUFF

WAIT FOR CR

172

24

0049

7 E

0006

J MP

NEXTCMD

173

3R

004 C

CE

0125

EXIT

LDX

0RESMSG

RESET CT-82

1 74

12 *

004 F

BD

ADI E

JSR

PSTRNG

175

1 5

0052

7E

A d03

J MP

WARMS

RETURN TO FLEX

176

*

177

0055

DRAW

EQU

*

DRAW POINT OR LINE

178

2 R

0055

81

50

CMP

A

#C ' P '

179

6

0057

27

07 (0060)

BEQ

DRAW.PT

180

2R

0059

81

4C

CMP

A

# C ' L '

181

6

00 5B

27

12 (006 F )

BEQ

DRAW.LN

182

3R

00 5 D

7E

0040

J MP

INPERR

INPUT ERROR

183

9R*

0060

B0

00 D 4

DRAW . PT

JSR

INTW0

GET X AND Y

184

14

0063

FE

0149

LDX

X . AND . Y

GET X AND Y

185

20

0066

F F

01 2 F

ST X

DPX

SAVE IN STRING

186

23

0069

CE

01 2 D

LDX

#DP

187

26

006C

7E

00B9

J MP

SEND

SEND IT

188

*

189

006 F

DRAW.LN

EQU

*

190

9R*

006 F

BD

00C8

JSR

INF0UR

GET U, V, X, AND Y

191

1 4

0072

FE

0147

LDX

U. AND.V

192

20

0075

F P

0134

STX

DLU

193

25

0078

FE

0149

LDX

X. AND. Y

194

31

007B

F F

0136

STX

DLX

195

34

007E

CE

0132

LDX

*DL

196

37

0081

7E

00B9

J MP

SEND

197

*

1 98

0084

ERASE

EQU

*

ERASE LINE OR POINT

199

2 R

0084

81

50

CMP

A

#C'P'

POINT?

200

6

0086

27

07 (008 F )

BEQ

ERS.PT

YES

201

2R

0088

81

4C

CMP

A

#C'L'

LINE?

202

6

008 A

27

12 (009E)

BEQ

ERS.LN

YES

203

3 R

008 C

7E

0040

J MP

INPERR

ERROR

204

9R*

008 F

BD

00D4

ERS.PT

JSR

INTWO

GET X AND Y

205

14

0092

FE

0149

LDX

X.AND.Y

206

20

0095

F F

01 3B

STX

EPX

207

23

0098

CE

0139

LDX

U EP

Microcomputing, October 1980 143

208

26 009B

7E

00B9

JMP

SEND

209

9 R* 009E

BD

00C8

ERS.LN

JSR

INFOUR

210

14 00A1

FE

0147

LDX

U. AND.V

211

20 00A4

FF

0140

STX

ELU

212

25 00A7

FE

0149

LDX

X.AND.Y

213

31 00AA

FF

0142

STX

ELX

214

34 00 AD

CE

013E

LDX

#E L

215

37 00B0

7E

00B9

JMP

SEND

216

*

217

00B3

CLEAR

EQU

*

218

3R 00B3

CE

012A

LDX

0CLRMSG

219

6 00B6

7 E

00B9

JMP

SEND

220

*

221

00B9

SEND

EQU

★

222

5 R 00B9

A6

00

L D A

A

o,x

223

9 00BB

08

I NX

224

11 00BC

81

FF

CMP

A

#X ' F F '

225

15 00BE

26

03 (00C3)

BNE

$10

226

3 R 00C0

7E

0006

JMP

NEXTCMD

227

9R * 00C3

BD

El 01

$10

JSR

0UTEEE

228

13 00 C 6

20

FI (00B9)

BRA

SEND

229

*

230

00C8

INFOUR

EQU

*

231

9R* 0 0 C 8

BD

00E 1

JSR

GETDEC

232

14 00CB

B7

0147

STA

A

U

233

23 * 00CE

BD

00E 1

JSR

GETDEC

234

28 00 D 1

R 7

0148

STA

A

V

235

00 D 4

INTW0

EQU

*

236

9R * 00D 4

BD

00E 1

JSR

GETDEC

237

14 00D7

B 7

0149

STA

A

EX

238

23 * 00DA

BD

00E 1

JSR

GETDEC

239

28 00DD

B 7

01 4 A

STA

A

Y

240

33 00E0

3 9

RTS

241

*

242

00E 1

GETDEC

EQU

*

243

9R* 00E 1

BD

AD48

JSR

INDEC

244

15 00E4

FF

0145

STX

TEMP

245

19 00E7

B6

0146

L D A

A

TEMP+1

246

24 00E A

39

RTS

GET U, V , X, AND Y

ERASE SCREEN

SEND STRING AND LOOP TO
NEXT COMMAND
GET CHARACTER

SPECIAL TERMINATOR?

NO

GET 4 DECIMAL NUMBERS U

,V,X,Y

U

GET 2 DECIMAL NUMBERS X
X

RETURN VALUE IN A

GET VALUE FROM LINE BUF

FER

SAVE

GET L.O. BYTE

248

OOEB

1 D 1 6

SMSG

CON

DX ' 1 D 1 6 '

PUT IN GRAPHICS MODE

249

00 E D

0000

CON

0,0

KILL SOME TIME

250

OOEF

1 E 1 8

CON

DX ' 1 E18'

DISABLE SCROLLING

251

00F1

04

CON

X ' 04 '

252

OOF 2

0B0015

PROMPT

CON

X 'OB' ,DX '

0015' CURSOR POS

253

00 F 5

16

CON

X ' 1 6 '

CLEAR TO END OF FRAME

254

00 F 6

434F4D4D41 4E

CON

C 'COMMAND

: ' , X ' 04 '

255

00 FF

0B0015

I E MSG

CON

X ' OB ' , DX ’

0015' CURSOR POS

256

0102

494E56414C49

CON

C ' INVALID

INPUT - '

257

0112

52455455524E

CON

C 'RETURN

TO CONTINUE* ,X'04'

258

0125

1 C 1 1

RESMSG

CON

DX ' 1 Cl 1 '

RESTORE FORMAT 1

259

0127

1 E 08

CON

DX ' 1 E08 '

ENABLE SCROLL

260

01 29

04

CON

X

o

■T'

261

01 2A

1 C16

CLRMSG

CON

D X ' 1 C 1 6 '

CLEAR TO BEGINNING OF F

RAME

262

012C

FF

CON

X' FF '

263

*

264

01 2 D

1 D 1 3

DP

CON

DX ' 1 D1 3'

DRAW PT. COMMAND

265

01 2 F

0000

DPX

CON

0,0

X,Y

266

01 31

FF

CON

X' FF'

267

*

268

01 32

1 D 03

DL

CON

D X ' 1 D03 '

DRAW LINE COMMAND

269

01 34

0000

DLU

CON

0,0

u,v

270

0136

0000

DLX

CON

0,0

X , Y

271

01 38

FF

CON

X' FF'

272

★

273

0139

1 D 1 4

EP

CON

DX ' 1 D1 4 '

ERASE PT. COMMAND

274

01 3B

0000

EPX

CON

0,0

X , Y

275

01 3D

FF

CON

X' FF '

276

*

277

013E

1 D04

EL

CON

DX '1 D04'

ERASE LINE COMMAND

278

0140

0000

ELU

CON

0,0

U,V

279

0142

0000

ELX

CON

0,0

X,Y

280

0144

FF

CON

X' FF'

281

*

282

0145

TEMP

RMB

2

283

0147

U. AND . V

EQU

★

284

01 47

U

RMB

1

285

0148

V

RMB

1

286

0149

X.AND.Y

EQU

*

287

0149

EX

RMB

1

288

014A

Y

RMB

1

289

*

290

01 4B

LAST

ENT

291

014B

END

START

AD36

ADDBX

66

AD21

CLASS

59

00B3

CLEAR

217

159

01 2A

CLRMSG

261

218

ADOO

COLDS

48

0132

DL

268

195

0134

DLU

269

192

0136

DLX

270

194

AD4B

DOCMND

73

01 2D

DP

264

186

01 2F

DPX

265

185

0055

DRAW

177

162

006 F

DRAW . LN

189

181

0060

DRAW.PT

183

179

013E

EL

277

21 4

0140

ELU

278

211

0142

ELX

279

213

01 39

EP

273

207

013B

EPX

274

206

0084

ERASE

198

165

009E

ERS.LN

209

202

008 F

ERS.PT

204

200

Photo 3. Sample run of TEST82.

loop.

Subroutine DRAW determines if the next
character is an L or P. An L causes control
to be transferred to DRAW.LN, which, in
turn, calls INFOUR to get the coordinates
and then draws a line. P causes control to
be transferred to DRAW.PT, which calls IN-
TWO to get the coordinates and then dis-
plays the specified point.

Note that the actual transmission of the
control strings is performed by routine
SEND. The Flex routine PSTRNG cannot be
used because a control string could contain
a hexadecimal 04, which acts as a string ter-
minator. SEND uses a hexadecimal FF as
the string terminator.

Subroutine ERASE works just like DRAW
except the clear control string is sent in-
stead of the set control string. ERS.PT
erases a point, and ERS.LN erases a line. To
output the control string, all of these rou-
tines use SEND, which transfers control
back to NEXTCMD.

Subroutine CLEAR sends an erase-to-
the-beginning-of-frame command to the
CT-82. This is sufficient, since the cursor is
on the last line of the screen, which will be
changed by NEXTCMD anyway. EXIT re-
stores the CT-82 to screen format 1 (82 x 16
with standard ROM), enables scrolling and
returns control to Flex.

Once I had a chance to play with TEST82
and get a feel for the graphics potential of
the CT-82, 1 decided it was time to interface
these capabilities to BASIC. I could either
write obscure subroutines in BASIC to send
out the control strings or modify TEST82 to
be callable from BASIC. I chose the latter
approach because it would make the BASIC
programs look more readable and be more
efficient. Besides, some assembly lan-
guage would be required anyway to handle
the hexadecimal 04 control characters. List-
ing 3, program BAS82, was the result.

BAS82

BAS82 differs from TEST82 in that it
picks up its commands from the buffer
pointed to by the contents of address 26
(hex) and has an added command, IN, which
initializes the CT-82 to graphics mode. Oth-
erwise, the two routines are essentially the

144 Microcomputing, October 1980

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3355 \

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i/ 0 Reader Service index— page 241

Microcomputing, October 1980 145

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0149

EX

287

237

000A

FEXT.PRT

135

004C

EXIT

173

168

0006

FEXT. SCR

131

AC00

F2BACK

8

0004

FEXT. SYS

129

A C29

F2CC0L

39

0001

FEXT .TXT

126

AC28

F2C0MF

38

0000

F L 2 1 0

80

A Cl 8

F2CURC

26

0016

FM2B0R

99

A C01

F2DEL

9

0004

FM2CLF

84

AC03

F2DEPC

11

OOOC

FM2DLF

91

A C07

F2DX

15

0014

FM2FND

97

A C08

F2EJC

16

0007

FM2GIR

87

AC2D

F2ENV

41

0011

FM2GRB

95

AC02

F2E0L

10

000 F

FM2NSS

93

A C 1 6

F2ERR

25

0006

FM20PD

86

A C 20

F2ERRT

32

0001

FM20PR

81

AC0A

F2ESC

18

0003

FM20PU

83

A840

F2FCB

43

0002

FM20PW

82

AC26

F2FIA

37

0010

FM20SI

94

AC2F

F2FIEF

42

0008

FM2PIR

88

AC24

F2F0A

36

0015

FM2P0S

98

AC23

F2INSW

35

0012

FM2PRB

96

A C 1 1

F2LAST

22

oo od

FM2RNF

92

A C 1 4

F2LBP

24

0009

FM2RSS

89

A080

F2LBUF

7

0005

FM2RWF

85

AC1B

F2LDA0

29

000A

FM2WSS

90

AC1 A

F2LINE

28

B400

FM IN IT

74

AC2B

F2MEND

40

B406

F MS

76

A C05

F2NULL

13

B403

FMSCLS

75

AC22

F20TSW

34

A D 1 5

GETCHR

55

AC09

F2PAUS

17

00E1

GETDEC

242

AC19

F2PREC

27

AD2D

G6TFIL

63

AC0E

F2SDR

21

A D42

GETHEX

70

AC0B

F2SDRV

19

00FF

IEMSG

255

A C21

F2SI0F

33

A D 1 B

INBUFF

57

A C 06

F2TABC

14

A D09

INCH

51

ACID

F2TRAN

30

AD0C

INCH2

52

AC1E

F2TRNA

31

AD48

INDE C

72

A 1 00

F2UCA

44

00C8

INF0UR

230

A C 1 2

F2UCTA

23

0040

INPERR

169

AC0C

F2WDRV

20

00D4

INTWO

235

A C04

F2WIDC

12

01 4B

LAST

290

0002

FB2ACT

105

A D 30

LOAD

64

0040

FB2BUF

122

0006

NEXT CMD

144

002 F

FB2CDA

119

AD27

NXTCH

61

001 E

FB2CUR

1 1 5

AD45

0UTADR

71

0003

FB2DRV

106

AD0F

0UTCH

53

001 3

FB2EDA

111

ADI 2

OUT C H 2

54

0001

FB2ESB

1 04

A D 39

0UTDEC

67

oooc

FB2EXT

108

El D1

0UTEEE

140

000 F

FB2FAT

109

AD3C

0UTHEX

68

0032

FB2FDP

120

AD24

PCRLF

60

001 C

FB2FLP

114

00 F 2

PROMPT

252

0000

FB2FNC

103

ADI E

PSTRNG

58

0022

FB2INX

116

A D 1 8

PUT CHR

56

0004

FB2NAM

107

AD06

RENTER

50

0024

FB2NWB

118

01 25

RESMSG

258

0023

FB2RDX

117

AD3F

RPTERR

69

003B

FB2SCF

121

A D 2 A

RSTRI0

62

0011

FB2SDA

110

00B9

SEND

221

0015

FB2SIZ

112

AD33

SETEXT

65

0017

FB2SMI

113

00 EB

SMSG

248

0008

FEXT .BAC

133

0000

START

141

0005

FEXT.BAK

130

0145

TEMP

282

0003

FEXT. BAS

128

0147

U

284

0000

FEXT.BIN

125

0147

U. AND.V

283

0002

FEXT.CMD

127

0148

V

285

0007

FEXT.DAT

132

AD03

WARMS

49

0009

FEXT .DIR

134

01 49

X . AND . Y

286

000B

FEXT. OUT

136

01 4 A

Y

288

231 233 236 238

169

146 171

243

190 209

149 167 182 203

183 204

172 226

147 151 153

227

144

143 145 1 70 174

187 196 208 215 219 228

1 42
291

244 245

232

191 210

234
1 75

184 193 205 212

Listing 2. Dummy program that shows all the Flex entry equates and their values.

1

2

0000

* :0. FLEXEQU

NAM
1. INC

DUMMY

- FOR LIST OF FLEXEQU. I
NC

3

A080

F2LBUF

EQU

X ' A080 '

LINE BUFFER

4

AC00

F2BACK

EQU

X* ACOO'

BACKSPACE CHARACTER

5

AC01

F2DEL

EQU

X • AC01 '

DELETE CHARACTER

6

AC02

F2E0L

EQU

X' AC02'

END OF LINE CHAR.

7

AC03

F2DEPC

EQU

X ' AC03'

PAGE DEPTH COUNT

8

AC 04

F2WIDC

EQU

X' AC04'

WIDTH COUNT

9

AC05

F 2 NULL

EQU

X* AC05'

NULL COUNT

10

AC06

F2TABC

EQU

X' AC06'

TAB CHARACTER

11

A C07

F2DX

EQU

X ' AC07'

DUPLEX MODE

12

A C08

F2EJC

EQU

X ' A C08 '

EJECT COUNT

13

A C09

F2PAUS

EQU

X' AC09'

PAUSE CONTROL

14

AC0A

F2ESC

EQU

X ' ACOA'

ESCAPE CHARACTER

1 5

AC0B

F2SDRV

EQU

X ' ACOB'

SYSTEM DRIVE NUMBER

16

A C0C

F2WDRV

EQU

X ' A CO C 1

WORKING DRIVE

17

ACOE

F2SDR

EQU

X ' ACOE '

3 BYTE DATE REGISTER

18

AC 1 1

F2LAST

EQU

X ' AC1 1 '

LAST TERMINATOR

19

AC1 2

F2UCTA

EQU

X' AC12'

USER COMMAND TABLE ADDR
ESS

20

AC 1 4

F2LBP

EQU

X ' AC1 4 1

LINE BUFFER POINTER

21

A C 1 6

F2ERR

EQU

X' AC16'

ESCAPE RETURN REGISTER

22

A Cl 8

F2CURC

EQU

X' AC18*

CURRENT CHARACTER

23

A C 1 9

F2PREC

EQU

X* AC19*

PREVIOUS CHARACTER

24

A C 1 A

F2LINE

EQU

X ' A C 1 A '

CURRENT LINE NUMBER

25

A C 1 B

F2LDA0

EQU

X 1 A C 1 B '

LOADER ADDRESS OFFSET

26

AC1 D

F2TRAN

EQU

X ' A C 1 D '

TRANSFER FLAG

27

AC1E

F2TRNA

EQU

X'ACIE'

TRANSFER ADDRESS

28

A C2 0

F2ERRT

EQU

X ' AC20 '

ERROR TYPE

29

AC21

F2SI0F

EQU

X’ AC21 '

SPCIAL I/O FLAG

30

AC22

F20TSW

EQU

X ' AC22 '

OUTPUT SWITCH

31

A C2 3

F2INSU

EQU

X ' AC23*

INPUT SWITCH

146 Microcomputing, October 1980

3 2

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52
33

54

55
36

57

58

59

60
61
6 2
65

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80
81
82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99
100
101
102
103
1 04
1 05
106

107

108

109

110
111
1 1 2

113

114

115

116

117

118

119

120
121
1 22
1 23
1 24

125

126

127

128

129

130

131

132

133

134

AC24

F2F0A

EQU

X ' AC24 1

FILE OUTPUT ADDRESS

AC26

F2 F I A

EQU

X' AC26'

FILE INPUT ADDRESS

A C 2 8

F2C0MF

EQU

X’ AC28'

COMMAND FLAG

A C29

F2CC0L

EQU

X* AC29'

CURRENT OUTPUT COLUMN

AC2B

F2MEND

EQU

X ' A C2B '

MEMORY END

AC2D

F2ENV

EQU

X ' AC2D '

ERROR NAME VECTOR

AC2F

F2FIEF

EQU

X ' A C2 F '

FILE INPUT ECHO FLAG

A840

F2FCB

EQU

X • A840 '

SYSTEM FCB

A100

F2UCA

EQU

X' A100'

UTILITY COMMAND AREA

* FLEX SUBROUTINES

AD00

COLDS

EQU

X ' ADOO '

COLDSTART ENTRY

AD03

WARMS

EQU

X' AD03'

WARM START ENTRY

A DO 6

RENTER

EQU

X’ AD06'

MAIN LOOP RE-ENTRY

A D09

INCH

EQU

X ' AD09 '

INPUT CHAR

adoc

INCH2

EQU

X 'ADOC '

INPUT CHAR

AD0F

0UTCH

EQU

X' ADOF '

OUTPUT CHAR

ADI 2

0UTCH2

EQU

X ' ADI 2 '

OUTPUT CHAR

ADIS

GETCHR

EQU

X ' A D 1 5 '

PREFERRED GET CHAR

A D 1 8

PUT CHR

EQU

X ' A D 1 8 '

preferred PUT CHAR

ADI B

INBUFF

EQU

X'ADIB'

INPUT TO LINE BUFFER

ADI E

PSTRNG

EQU

X ' AD1E '

PRINT STRING

A D 2 1

CLASS

EQU

X ’ AD21 '

CLASSIFY CHARACTER

AD24

PCRLF

EQU

X ' AD24 '

PRINT C R , LF

AD27

NXTCH

EQU

X' AD27'

NEXT CHARACTER

A D 2 A

RSTRI0

EQU

X ' AD2 A '

RESTORE I/O VECTORS

AD2D

GETFIL

EQU

X ' AD2D '

PARSE FILE SPEC.

AD30

LOAD

EQU

X ' AD30 '

FILE LOADER

A D 33

SETEXT

EQU

X' AD33'

SET EXTENSION

A D 36

ADDBX

EQU

X' AD36*

ADD ACC-B TO X

A D 39

0UTDEC

EQU

X 1 AD39 '

OUTPUT DECIMAL NUMBER

AD3C

0UTHEX

EQU

X ' AD3C '

OUTPUT HEX CHARACTER

A D 3 F

RPTERR

EQU

X ' AD3F '

REPORT ERROR

AD42

GETHEX

EQU

X ' AD42 '

GET HEX NUMBER

AD45

0UTADR

EQU

X ' AD45 '

OUTPUT HEX ADDRESS

AD48

INDEC

EQU

X ' AD48 '

INPUT DECIMAL NUMBER

AD4B

D0CMND

EQU

X 1 A D4B '

CALL DOS

B 400

FMINIT

EQU

X ' B400 '

FMS INITIALIZATION

B403

FMSCLS

EQU

X ' B403 '

FMS CLOSE

B406

FMS

EQU

X 'B406'

FMS CALL

* FMS COMMANDS

0000

FL2I0

EQU

X'O'

READ/WRITE NEXT BYTE

0001

FM20PR

EQU

X • 1 •

OPEN FOR READ

0002

FM20PW

EQU

X '2 '

OPEN FOR WRITE

0003

FM20PU

EQU

X '3'

OPEN FOR UPDATE

0004

F M2 CL F

EQU

X '4 '

CLOSE FILE

0005

FM2RWF

EQU

X 1 5 '

REWIND FILE

0006

FM20PD

EQU

X '6'

OPEN DIRECTORY

0007

FM2GIR

EQU

X 1 7 '

GET INFORMATION RECORD

0008

FM2PIR

EQU

X ' 8 '

PUT INFORMATION RECORD

0009

FM2RSS

EQU

X '9 '

READ SINGLE SECTOR

000A

FM2WSS

EQU

X ' A •

WRITE SINGLE SECTOR

oooc

FM2DLF

EQU

X'C'

DELETE FILE

00 0 D

FM2RNF

EQU

X ' D '

RENAME FILE

000 F

F M2 NS S

EQU

X ' F '

NEXT SEQUENTIAL SECTOR

0010

FM20SI

EQU

X'10'

OPEN SYSTEM INFORMATION

RECORD

0011

FM2GRB

EQU

X '1 1 '

GET RANDOM BYTE FROM SE
CTOR

0012

FM2PRB

EQU

X 1 1 2 '

PUT RANDOM BYTE IN SECT
OR

0014

FM2FND

EQU

X ' 1 4 '

FIND NEXT DRIVE

0015

FM2P0S

EQU

X * 1 5 '

POSITION BY RECORD

0016

FM2B0R

EQU

X ' 1 6 1

BACKUP 1 RECORD

* FILE CONTROL

BLOCK SPECIFICATIONS

0000

FB2FNC

EQU

0

FMS COMMAND

0001

FB2ESB

EQU

1

ERROR STATUS

0002

FB2ACT

EQU

2

ACTIVITY STATUS

0003

FB2DRV

EQU

3

DRIVE NUMBER

0004

FB2NAM

EQU

4

FILE NAME (8 BYTES)

OOOC

FB2EXT

EQU

12

EXTENSION (3 BYTES)

000 F

FB2FAT

EQU

15

FILE ATTRIBUTES

0011

FB2SDA

EQU

17

STARTING DISK ADDRESS

0013

FB2EDA

EQU

19

ENDING DISK ADDRESS

0015

FB2SIZ

EQU

21

FILE SIZE

0017

FB2SMI

EQU

23

FILE SECTOR MAP INDICAT
OR

001 C

FB2FLP

EQU

28

FCB LIST POINTER

001 E

FB2CUR

EQU

30

CURRENT POSITION

0022

FB2INX

EQU

34

DATA INDEX

0023

FB2RDX

EQU

35

RANDOM INDEX

0024

FB2NWB

EQU

36

NAME WORK BUFFER

002 F

FB2CDA

EQU

47

CURRENT DIRECTORY ADDRE
SS

0032

FB2FDP

EQU

50

FIRST DELETED DIRECTORY

POINTER

003 B

FB2SCF

EQU

59

SPACE COMPRESSION FLAG

0040

FB2BUF

EQU

64

SECTOR BUFFER

* FILE EXTENSIONS

0000

FEXT .BIN

EQU

0

0001

FEXT.TXT

EQU

1

0002

FEXT . CMD

EQU

2

0003

FEXT. BAS

EQU

3

0004

FEXT. SYS

EQU

4

0005

FEXT .BAK

EQU

5

0006

FEXT .SCR

EQU

6

0007

FEXT . DAT

EQU

7

0008

FEXT . BAC

EQU

8

0009

FEXT .DIR

EQU

9

000A

FEXT .PRT

EQU

10

000B

FEXT .OUT

EQU

1 1

0000

END

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Two serial RS232 ports, I/O ports standard.
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- WRITE FOR FREE CATALOG - ^ 304

1618 James Street
Syracuse, NY 13203 (315) 422-4467

iS Reader Service index— page 241

Microcomputing, October 1980 147

same. I load BAS82 at address C800, where
I have some free memory. The program
must be loaded somewhere that BASIC
doesn’t know about so it isn’t wiped out.

Next, I wrote a set of subroutines in BA-
SIC that called the different functions in
BAS82. These subroutines appear in lines
9000 through 9630 in Listings 4, 5 and 6.
Lines 9000 through 9070 comprise the ini-
tialization subroutine. They call the system
loader to load BAS82, set the BAS82 entry
point in the location BASIC uses for the ad-
dress of the USR function, call BAS82 with a
parameter value of “IN” and turn off the cur-
sor display.

Lines 9100 through 9140 draw a point.
Note that X is the column coordinate with
valid values from 0 to 183. Y is the row coor-
dinate with valid values from 0 to 65.

The draw-line subroutine in lines 9200
through 9240 uses variables U and V as the
column and row coordinates of one end of
the line, and variables X and Y as the col-
umn and row coordinates of the other end.
Again, BAS82 is called to transmit the ap-
propriate control string to the CT-82.

The clear subroutine in lines 9300
through 9340 sends a clear screen com-
mand. The exit subroutine in lines 9400
through 9450 restores the CT-82 to non-
graphics mode and turns on the cursor.

The erase line subroutine in lines 9500
through 9540 and the erase point subrou-
tine in lines 9600 through 9630 work the
same as their equivalent draw subroutines.

Using these subroutines, I wrote three
BASIC programs. The first, Random Draw/
Erase Line (Listing 4), generates coordi-
nates randomly, draws a line, generates an-
other set of random coordinates, erases a
line and then repeats this loop the specified
number of times. Although this is much
more interesting to watch when it is running
than after it has stopped, Photo 4 shows
how it appears.

Listing 5 shows a more practical program
that draws a sine curve (see Photo 5). It
essentially uses the equation Y = SIN(X).
Lines 310 and 320 look strange but they
handle the scaling for the screen dimen-
sions; lower values of Y will cause the curve
to move up on the screen. Also, line 420
positions the cursor and labels the graph.

The third program (Listing 6) generates a
bar graph (see Photo 6). This graph shows
the frequency distribution of the function
x = RND(0)*20 for 600 trials. In other words,
it shows how random the random number
generator is by trying it 600 times and
graphically displaying the result. The bar-
graphing technique is useful in displaying
data for easy comparison.

This is currently where I am in exploring
the capabilities of the CT-82. Using the
basic concepts presented in this article,
you will be able to discover even more. ■

Listing 3. BAS82.

1

0000

NAM

BAS82

2

* CT82-I

BASIC GRAPHICS INTERFACE

3

* SSC 8

-16-79 VI .

.7

137

0000

OPT

PNT,XRF

138

★

139

El D1

0UTEEE

EQU

X ' E 1 D 1 '

USED FOR FUNNY CHARACTE

RS

140

0026

PASS

EQU

X ' 26 '

ADDRESS PASSED BY BASIC

141

*

142

0000

BAS. 82

ENT

143

4R

0000

DE

26

LDX

PASS

DESCRIPTOR ADDRESS

144

10

0002

EE

00

LDX

0,X

STRING ADDRESS (PACKET)

145

16

0004

FF

0134

STX

PKTADR

SAVE

146

21

0007

E6

00

LDA

B

0 / x

GET

147

26

0009

A6

01

L D A

A

1 ,x

FUNCTION

148

*

149

28

000B

Cl

49

CMP

B

#CT

INITIALIZE?

150

32

00 0D

26

07 (0016)

BNE

$5

151

2R

000 F

81

4E

CMP

A

# C ' N 1

152

6

0011

26

03 (0016)

BNE

$5

153

3 R

001 3

7E

00B7

JMP

IN IT

YES - INITIALIZE CT82

154

0016

$ 5

NUL

155

2 R

0016

Cl

43

CMP

B

#C' C '

CLEAR?

156

6

0018

26

07 (0021)

BNE

$8

157

2 R

001 A

81

53

CMP

A

#C'S’

CS - CLEAR SCREEN ?

158

6

001 C

26

03 (0021)

BNE

$8

159

3R

001 E

7E

00B1

JMP

CLEAR

160

2R

0021

Cl

44

$8

CMP

B

nz ’ D '

DRAW?

1 61

6

0023

26

03 (0028)

BNE

$10

NO

162

3R

0025

7E

0053

JMP

DRAW

163

2 R

0028

Cl

45

$10

CMP

B

#C ' E '

ERASE?

164

6

002A

26

03 ( 002 F )

BNE

$12

NO

165

3R

002 C

7E

0082

JMP

ERASE

166

2R

002 F

Cl

58

$12

CMP

B

# ex'

EXIT?

167

6

0031

26

03 (0036)

BNE

INPERR

168

3R

0033

7E

0040

J MP

EXIT

169

3R

0036

CE

00E 0

INPERR

LDX

# I E MSG

170

12 *

0039

B0

00 B 0

JSR

SEND

ERROR MESSAGE

171

21 *

003 C

Bt)

A 0 1 B

JSR

INBUFF

WAIT FOR CR

172

26

003 F

39

RTS

173

3 R

0040

CE

0113

EXIT

LOX

# RE S MSG .

,1 RESET CT-82

174

12 *

0043

B0

00BD

JSR

SEND

175

1 5

0046

CE

FFFF

LDX

#X 'FFFF'

WAIT A WHILE

176

4 R

0049

09

$5

OEX

177

8

004 A

26

FD (0049)

BNE

$5

1 78

3R

004 C

CE

0116

LDX

# RE SMSG .

,2 RESTORE SCROLLING

179

12 *

004 F

B0

00BD

JSR

SEND

180

17

0052

3 9

RTS

RETURN TO BASIC

181

*

182

0053

DRAW

EQU

*

DRAW POINT OR LINE

183

2R

0053

81

50

CMP

A

#C'P'

184

6

0055

27

07 (005E)

BEQ

DRAW.PT

185

2 R

0057

81

4C

CMP

A

#C'L'

186

6

0059

27

12 (0060)

BEQ

DRAW.LN

187

3R

005 B

7E

0036

JMP

INPERR

INPUT ERROR

188

9R*

005E

BD

0008

ORAW.PT

JSR

INTWO

GET X AND Y

189

1 4

0061

FE

013A

LDX

X . AND . Y

GET X AND Y

190

20

0064

FF

01 1 E

STX

DPX

SAVE IN STRING

191

23

0067

CE

011 C

LDX

#DP

192

26

006A

7E

00BD

JMP

SEND

SEND IT

193

*

194

006 D

DRAU.LN

EQU

*

195

9R *

006D

BD

00 CB

JSR

INFOUR

GET U, V , X, AND Y

196

1 4

0070

FE

0138

LDX

U . AND .V

197

20

0073

FF

0123

STX

DLU

198

25

0076

FE

01 3 A

LDX

X . AND . Y

199

31

0079

FF

0125

STX

DLX

200

34

007 C

CE

01 21

LDX

#DL

201

37

00 7 F

7E

00BD

JMP

SEND

202

*

203

0082

ERASE

EQU

*

ERASE LINE OR POINT

204

2 R

0082

81

50

CMP

A

#C'P'

POINT?

205

6

0084

27

07 (0080)

BEQ

ERS.PT

YES

206

2 R

0086

81

4C

CMP

A

#C'L'

LINE?

207

6

0088

27

12 (0090

BEQ

ERS.LN

YES

208

3 R

008A

7E

0036

JMP

INPERR

ERROR

209

9R*

0080

BD

0008

ERS.PT

JSR

INTWO

GET X AND Y

210

1 4

0090

FE

013A

LDX

X . AND . Y

211

20

0093

FF

01 2 A

STX

EPX

21 2

23

0096

CE

01 28

LDX

#EP

213

26

0099

7E

OOBD

JMP

SEND

214

9R*

009C

BD

00CB

ERS.LN

JSR

INFOUR

GET U, V / X, AND Y

215

1 4

009 F

FE

0138

LDX

U. AND.V

216

20

00A2

FF

01 2F

STX

ELU

217

25

00A5

FE

013A

LDX

X . AND . Y

218

31

00A8

FF

0131

STX

ELX

219

34

00 AB

CE

0120

LDX

#EL

220

37

00 AE

7E

OOBD

JMP

SEND

221

*

222

00B1

CLEAR

EQU

*

ERASE SCREEN

223

3R

00B 1

CE

0119

LDX

tt CLRMSG

224

6

00B4

7E

00B0

JMP

SEND

22 5

*

226

00B7

I N IT

EQU

★

INITIALIZE CT-82

227

3R

00B7

CE

00E6

LDX

#SMSG

228

6

00BA

7E

OOBD

JMP

SEND

229

*

230

00BD

SEND

EQU

if

SEND STRING AND LOOP TO

NEXT COMMAND

231

5 R

00 B 0

A6

00

LDA

A

o,x

GET CHARACTER

232

9

00BF

08

I NX

233

11

ooco

81

FF

CMP

A

#X ' FF '

SPECIAL TERMINATOR?

234

15

00 C 2

26

01 (00C5)

BNE

$10

NO

235

20

OOC4

39

RTS

148 Microcomputing, October 1980

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^59

iS Reader Service index— page 241

Microcomputing, October 1980 149

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237

13

00 C 8

20 F 3 (00BD)

238

18

00CA

39

239

*

240

00CB

INF0UR

241

5 R

00 C B

FE 0134

242

10

00CE

A6 04

243

15

00D0

B7 0138

244

20

0003

A6 05

245

25

00D5

B7 0139

246

00 D 8

INTWO

247

5 R

00D 8

FE 0134

248

10

00 D B

A6 02

249

15

00DD

B7 01 3 A

250

20

00E0

A6 03

251

25

00E2

B7 013B

252

30

00E 5

39

253

*

254

*

255

00E6

1 D 1 6

SMSG

256

00E8

0000

257

00 E A

1 E 1 8

258

00EC

FF

259

OOED

0B0015

IEMSG

260

00 F0

494E5641 4C49

261

0100

5245545552 4E

262

0113

1C1 1

RESMSG.1

263

0115

FF

264

0116

1 E08

RESMSG.2

265

011 8

FF

266

0119

101 6

CLRMSG

267

01 IB

FF

268

*

269

011 C

1013

DP

270

01 1 E

0000

DPX

271

0120

FF

272

*

273

0121

1 DO 3

DL

274

01 23

0000

DLU

275

0125

0000

DLX

276

0127

FF

277

*

278

01 28

1 D 1 4

EP

279

01 2 A

0000

EPX

280

012C

FF

281

*

282

01 2D

1D04

EL

283

01 2F

0000

ELU

284

0131

0000

ELX

285

0133

FF

286

*

287

0134

PKTADR

288

0136

TEMP

289

01 38

U. AND.V

290

01 38

U

291

0139

V

292

01 3A

X.AND.Y

293

01 3 A

EX

294

01 3B

Y

295

*

296

01 3C

LAST

297

013C

JSR

OUTEEE

SEND

IT

BRA

SEND

RTS

EQU

*

GET

4 DECIMAL NUMBER

,v,x

,Y

LDX

PKTADR

GET

PACKET ADDRESS

LD A

A

4,X

GET

U

STA

A

U

LD A

A

5,X

GET

V

STA

A

V

EQU

*

GET

2 DECIMAL NUMBER

/ Y

LDX

PKTADR

GET

PACKET ADDRESS

L D A

A

2,X

GET

X

STA

A

EX

LDA

A

3 , X

GET

Y

STA

A

Y

RTS

CON

DX • 1 D16 ’

PUT IN GRAPHICS MODE

CON

0,0

KILL SOME TIME

CON

D X 1 1 E 1 8 '

DISABLE SCROLLING

CON

X * FF *

CON

X 1 OB' , D X

'0015' CURSOR POS

CON

C ' INVALI

D INPUT - '

CON

C ' RETURN

TO CONTINUE ' ,X' FF '

CON

DX'ICII '

RESTORE FORMAT 1

CON

X ' FF '

CON

DX ' 1 E08 1

ENABLE SCROLL

CON

X' FF'

CON

D X ' 1 01 6 1

CLEAR SCREEN

CON

X ' FF '

CON

DX ' 1 D1 3'

DRAW PT. COMMAND

CON

0,0

X , Y

CON

X ' FF '

CON

DX ' 1 D03 '

DRAW LINE COMMAND

CON

0,0

u,v

CON

0,0

X , Y

CON

X' FF'

CON

D X ' 1 D 1 4 '

ERASE PT. COMMAND

CON

0,0

X , Y

CON

X ' FF '

CON

DX ' 1 D04 '

ERASE LINE COMMAND

CON

0,0

u,v

CON

0,0

X , Y

CON

X ' FF '

R MB

2

PACKET ADDRESS SAVE

RMB

2

EQU

*

RMB

1

RMB

1

EQU

*

RMB

1

RMB

ENT

END

1

Aurora Software Associates

353 South 1 00 East#6 ^193 )

Springville, Utah 84663

.GET, Paid
for using your
Computer e ®»

FUN' Eas'f

RUSH COUPON FOR ^
FREE FACTS

GP^SPARETIME

Send today to DAR M10B
31 10 Fulton Ave.. Sacramento CA 95821 ^ 136

#0

Photo 4. Sample output of random draw/erase line program .

Listing 4. Random draw/erase line program.

10 REM RANDOM DRAW/ERASE LINE

100 G0SUB 9000

200 G0SUB 9300

220 GOTO 1000

250 FOR 1=1 TO L

300 U=RND<0)*100

310 V=RND(0) *60

320 X=RND(0>*100

330 Y = RND (0) *60

400 G0SUB 9200 : REM DRAW A LINE
500 U=RND (0 ) *1 00
510 V=RND(0) *60

529 X=RND(0)*100

530 Y=RND(0)*60

150 Microcomputing, October 1980

REM ERASE A LINE

550 GOSUB 9500 :

900 NEXT I
1000 PRINT CHRS ( 1 1 );CHR$(0);CHR$(21);

1010 PRINT CHR$ (6 ) : REM ERASE TO EOL
1020 INPUT "ENTER LOOP COUNT";L
1040 IF L>0 THEN 250
1060 GOSUB 9400
1100 END

9000 REM INITIALIZE CT-82 GOSUB
9010 EXEC, "GET 1.BAS82.BIN"

9020 POKE HEX("24") ,HEX("C8") :POKE HE X ( "25 " ) , HE X ( "00" )
9030 ZZS=" IN"

9040 Z=USR(PTR(ZZ$) )

9050 PRINT CHRS(30);CHRS(21 ) :REM TURN OFF CURSOR
9060 RETURN
9070 REM ***

9100 REM DRAW POINT (X,Y) GOSUB
9110 ZZS="DP"+CHR$(X)+CHR$(Y)

9120 Z = USR ( PTR C ZZ$ ) )

9130 RETURN
9140 REM ***

9200 REM DRAW LINE (U,V,X,Y) GOSUB

9210 ZZS="DL"+CHRS(U)+CHRS(V)+CHR$(X)+CHR$(Y)

9220 Z=USR(PTR(ZZ$) )

9230 RETURN
9240 REM **

9300 REM CLEAR GOSUB
9310 ZZS="CS"

9320 Z=USR(PTR(ZZS) )

9330 RETURN
9340 REM ***

9400 REM EXIT GOSUB
9410 ZZS="X"

9420 Z = USR(PTR(ZZ$) )

9430 PRINT CHRS (30) ; CHRS (5 )

9440 RETURN
9450 REM ***

9500 REM ERASE LINE (U,V,X,Y) GOSUB

9510 ZZS="EL"+CHR$(U)+CHR$(V)+CHR$(X)+CHR$(Y)

9520 Z=USR(PTR(ZZ$) )

9530 RETURN
9540 REM ***

9600 REM ERASE POINT (X,Y) GOSUB
9610 ZZS="EP"+CHRS(X)+CHRS(Y>

9620 Z=USR(PTR(ZZS) )

9630 RETURN

Photo 5. Sample output from sine curve program.

Listing 5. Draw sine curve program.

10 REM DRAW SINE CURVE
100 GOSUB 9000

300 FOR 1=0 TO 2*P I STEP .05
310 X=20* I

320 Y=30*(1-SIN(I) )+1
350 GOSUB 9100
400 NEXT I

420 PRINT CHR$(11 ); CHRSC25); CHR$(21 ) ; " Y=S IN (X > ";

500 INPUT #0 , AS
600 GOSUB 9400
700 END

9000 REM INITIALIZE CT-82 GOSUB
9010 EXEC, "GET 1.BAS82.BIN"

9020 POKE HEX("24") ,HEX ("C8") :POKE HE X ( "2 5 " ) ,HE X ( "00" )
9030 Z Z$ = " IN"

9040 Z=USR(PTR(ZZS) )

9050 PRINT CHRS (30); CHRS (21 ): REM TURN OFF CURSOR
9060 RETURN
9070 REM ***

9100 REM DRAW POINT (X,Y) GOSUB
9110 ZZS="DP"+CHR$(X)+CHRS(Y)

9120 Z=USR(PTR(ZZS) )

9130 RETURN
9140 REM ***

9200 REM DRAW LINE (U,V,X,Y) GOSUB

9210 ZZ$="DL"+CHRS(U)+CHRS(V)+CHRS(X)+CHRS(Y)

9220 Z=USR(PTR(ZZS) )

9230 RETURN
9240 REM **

9300 REM CLEAR GOSUB
9310 ZZ$="CS"

9320 Z=USR(PTR(ZZ$))

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Reader Service index — page 241

Microcomputing , October 1980 151

If you’re serious
about the stock market,
you need

Tickertec"

Watch 48 to 400 of your favorite
stocks without a 1 5 minute delay.

Tickertec™ is a computer program that dis-
plays the NYSE or AMEX tickertape on your
TRS-80™ Model I or both exchanges as an
option on the Model II. You see every trade
as it is reported by the exchange and track
the last ten trades, tickertape reported
volume, and high and low limits on the
stocks you are watching. Tickertec pro-
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copy and portfolio management systems.
Programs may be purchased for cash (i.e.,
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in the form of discounted brokerage com-
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MaxUle& ^ 171

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PRINTER MECHANISM

Made by Binder Magnete for U.S. assembled 180 CPS
bidirectional matrix printer, 0-132 and 0-158 columns.
Includes single platen, ribbon drive, paper guides,
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operational. 75 lbs. sh. #MPM/M12 $125.

PRINT STAND for above, chocolate brown
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DATANETICS KEYBOARD

75 keys, ASCII encoded. +5 and -12 VDC required.
Keyboard assembled with unassembled case,
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CONTROLLER CPU, directed mechanical
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FIFO, 4/2111-1 RAM, 7400,
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9330 RETURN
9340 REM ***

9400 REM EXIT G0SUB
9410 ZZS="X"

9420 Z=USR(PTR(ZZ$) )

9430 PRINT CHRS(30); CHRSC5)

9440 RETURN
9450 REM ***

9500 REM ERASE LINE (U,V,X,Y) G0SUB

9510 ZZS="EL"+CHRS(U)+CHRS(V)+CHRS(X)+CHRS(Y)

9520 Z=USR(PTR(ZZ$) )

9530 RETURN
9540 REM ***

9600 REM ERASE POINT (X,Y) GOSUB
9610 ZZ$="EP"+CHR$(X)+CHR$(Y)

9620 Z=USR(PTR(ZZS) )

9630 RETURN

Photo 6. Output sample from bar graph program.

10 REM BAR GRAPH OF RANDOM NUMBER DISTRIBUTION
90 DIM V ( 20 )

100 GOSUB 9000
200 FOR 1=1 TO 600
210 X=KND(0)*20
220 V(X)=V(X)+1
230 NEXT I
300 V = 5 0

310 FOR 1=0 TO 20
320 X =6* I
330 Y=50-V(I>

340 U=X

350 GOSUB 9200
360 NEXT I

400 PRINT CHR$(11);CHRS(0);CHR$(18);

410 PRINT "0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 16 17 18 19 20"

420 PRINT

430 PRINT "DISTRIBUTION OF 600 RANDOM NUMBERS BETWEEN 0 AND 20"

500 INPUT #0,AS
600 GOSUB 9400
610 END

9000 REM INITIALIZE CT-82 GOSUB
9010 EXEC, "GET 1.BAS82.BIN"

9020 POKE HEXC'24") ,HEX("C8") :P0KE HEX ("25") , HEX ("00")

9030 Z Z$ = " IN"

9040 Z=USR(PTR(ZZ$) )

9050 PRINT CHR$(30); CHR$(21 ) : REM TURN OFF CURSOR
9060 RETURN
9070 REM ***

9100 REM DRAW POINT (X,Y) GOSUB
9110 ZZS="DP"+CHRS(X)+CHR$(Y)

9120 Z=USR(PTR(ZZS))

9130 RETURN
9140 REM ***

9200 REM DRAW LINE (U,V,X,Y) GOSUB

9210 ZZS="DL"+CHRS(U)+CHR$(V)+CHR$(X)+CHRS(Y)

9220 Z=USR(PTR(ZZS))

9230 RETURN
9240 REM **

9300 REM CLEAR GOSUB
9310 ZZS="CS"

9320 Z=USR(PTR(ZZ$))

9330 RETURN
9340 REM ***

9400 REM EXIT GOSUB
9410 ZZS="X"

9420 Z=USR (PTR ( ZZ$) )

9430 PRINT CHR$(30);CHRS(5)

9440 RETURN
9450 REM ***

9500 REM ERASE LINE (U,V,X,Y) GOSUB

9510 ZZ$="EL"+CHRS(U)+CHRS(V)+CHR$(X)+CHR$(Y)

9520 Z=USR (PTR (ZZS) )

9530 RETURN
9540 REM ***

9600 REM ERASE POINT (X,Y) GOSUB
9610 ZZ$="EP"+CHRS(X)+CHRS(Y)

9620 Z=USR (PTR ( ZZ*> )

9630 RETURN

Listing 6. Bar graph of random number distribution program.

152 Microcomputing, October 1980

NEW! TPM* for TRS-80 Model II
NEW! System/6 Package

Computer Design Labs

Z 80 Disk software

We have acquired the rights to all TDL software (& hardware). TDL software has long had the reputation of being the best in the
industry. Computer Design Labs will continue to maintain, evolve and add to this superior line of quality software.

— Carl Galletti and Roger Amidon, owners.

Software with Manual/Manual Alone

All of the software below is available on any of the
following media for operation with a Z80 CPU using
the CP/M* or similar type disk operating system
(such as our own TPM*).

for TRS-80* CP/M (Model I or II)
for 8” CP/M (soft sectored single density)
for 5y« M CP/M (soft sectored single density)
for S 1 /*” North Star CP/M (single density)
for S 1 /*” North Star CP/M (double density)

BASIC I

A powerful and fast Z80 Basic interpreter with EDIT,
RENUMBER, TRACE, PRINT USING, assembly language
subroutine CALL, LOADGO for “chaining”, COPY to
move text, EXCHANGE, KILL, LINE INPUT, error inter-
cept, sequential file handling in both ASCII and binary
formats, and much, much more. It runs in a little over 1 2
K. An excellent choice for games since the precision
was limited to 7 digits in order to make it one of the
fastest around. $49.95/$15.

BASIC II

Basic I but with 1 2 digit precision to make its power
available to the business world with only a slight sacrifice
in speed. Still runs faster than most other Basics (even
those with much less precision). $99.95/$15.

BUSINESS BASIC

The most powerful Basic for business applications. It
adds to Basic II with random or sequential disk files in
either fixed or variable record lengths, simultaneous
access to multiple disk files, PRIVACY command to
prohibit user access to source code, global editing,
added math functions, and disk file maintenance capa-
bility without leaving Basic (list, rename, or delete).
$1 79.95/$25.

ZEDIT

A character oriented text editor with 26 commands
and “macro" capabilityforstringing multiple commands
together. Included are a complete array of character
move, add, delete, and display function. $49.95./$15.

ZTEL

Z80 Text Editing Language - Not just a text editor.
Actually a language which allows you to edit text and
also write, save, and recall programs which manipulate
text. Commands include conditional branching, subrou-
tine calls, iteration, block move, expression evaluation,
and much more. Contains 36 value registers and 1 0 text
registers. Be creative! Manipulate text with commands
you write using Ztel. $79.95/$25.

TOP

A Z80 Text Output Processor which will do text
formatting for manuals, documents, and other word
processing jobs. Works with any text editor. Does
justification, page numbering and headings, spacing,
centering, and much more! $79.95/325.

MACRO I

A macro assembler which will generate relocateable
or absolute code for the 8080 or Z80 using standard
Intel mnemonics plusTDL/Z80 extensions. Functions
include 1 4 conditionals, 1 6 listing controls, 54 pseudo-
ops, 1 1 arithmetic/logical operations, local and global
symbols, chaining files, linking capability with optional
linker, and recursive/reiterative macros. This assembler
is so powerful you’ll think it is doing all the work for you. It
actually makes assembly language programming much
less of an effort and more creative. $79.95/320.

MACRO II

Expands upon Macro Fs linking capability (which is
useful but somewhat limited) thereby being able to take
full advantage of the optional Linker. Also a time and
date function has been added and the listing capability
improved. $99.95/$25.

LINKER

How many times have you written the same subro j.ine
in each new program? Top notch professional pro-
grammers compile a library of these subroutines and
use a Linker to tie them together at assembly time.
Development time is thus drastically reduced and
becomes comparable to writing in a high leve' language
but with all the speed of assembly language. So, get the
newCDL Linker and start writing programs in a fraction
of the time it took before. Linker is compatible with
Macro I & 1 1 as well as TDL/Xitan assemblers version 2.0
or later. $79.95/$20.

DEBUG I

Many programmers give up on writing in assembly
language even though they know their programs would
be faster and more powerful. To them assembly language
seems difficult to understand and follow, as well as
being a nightmare to debug. Well, not with proper tools
like Debug I. With Debug I you can easily follow the flow
of any Z80 or 8080 program. Trace the program one
step at a time or 1 0 steps or whatever you like. At each
step you will be able to seethe instruction executed and
what it did. If desired, modifications can then be made
before continuing. It’s all under your control. You can
even skip displaying a subroutine call and up to seven
breakpointscan be set during execution. Use of Debug I
can pay for itself many times overby savi ng you val uable
debugging time. $79.95/$20.

DEBUG II

This is an expanded debugger which has all of the
features of Debug I plus many more. You can “trap” (i.e.
trace a program until a set of register, flag, and/or
memory conditions occur). Also, instructions may be
entered and executed immediately. This makes it easy
to learn new instructions by examining registers/memory
before and after. And a RADIX function allows changing
between ASCII, binary, decimal, hex, octal, signed
decimal, or split octal. All these features and more add
up to give you a very powerful development tool. Both
Debug I and II must run on a Z80 but will debug both Z80
and 8080 code. $99.95/$20.

ZAPPLE

A Z80 executive and debug monitor. Capable of
search, ASCII put and display, read and write to 1/0
ports, hex math, breakpoint, execute, move, fill, display,
read and write in Intel or binary format tape, and more!
on disk

APPLE

8080 version of Zapple

NEW! TPM now available for TRS-80 Model
II!

TPM*

A NEW Z80 disk operation system! This is not CP/M*.
It’s better! You can still run any program which runs with
CP/M* but unlike CP/M* this operating system was
written specifically for the Z80* and takesfull advantage
of its extra powerful instruction set. In other words its
not warmed over 8080 code! Available for TRS-80*
(Model I or II). Tarbell, Xitan DDDC, SD Sales “VERSA-
FLOPPY", North Star (SD&DD), and Digital (Micro)
Systems. $79.95/$25.

SYSTEM MONITOR BOARD (SMB II)

A complete 1/0 board forS-1 00 systems. 2 serial ports,
2 parallel ports, 1200/2400 baud cassette tape inter-
face, sockets for2K of RAM, 3-2708/271 6 EPROM’s or
ROM, jump on reset circuitry. Bare board $49.95/$20.

ROM FOR SMB II

2KX8 masked ROM of Zapple monitor. Includes source
listing $34.95/$15.

PAYROLL (source code only)

The Osborne package. Requires C Basic 2.

5” disks $124.95 (manual not included)

8” disks $ 99.95 (manual not included)

Manual $20.00

ACCOUNTS PAYABLE/RECEIVABLE
(source code only)

By Osborne, Requires C Basic 2
5” disks $124.95 (manual not included)

8” $99.95 (manual not included)

Manual $20.00

GENERAL LEDGER (source code only)

By Osborne. Requires C Basic 2
5” disks $99.95 (manual not included)

8" disks $99.95 (manual not included)

Manual $20.00

SYSTEM/6

TPM with utilities, Basic I interpreter, Basic E compiler,
Macro I assembler, Debug I debugger, and ZEDIT text
editor.

Above purchased separately costs $339.75
Special introductory offer Only $1 79.75 with coupon!!

ORDERING INFORMATION

Visa, Master Charge and C.O.D. O.K. To order call or
write with the following information.

1 . Name of Product (e.g. Macro I)

2. Media (e.g. 8” CP/M)

3. Price and method of payment (e.g. C.O.D.) include
credit card info, if applicable.

4. Name, Address and Phone number.

5. ForTPM orders only: Indicate if forTRS 80, Tarbell,
Xitan DDDC, SD Sales (5V4” or 8”). ICOM (5V4” or
8"), North Star (single or double density) or Digital
(Micro) Systems.

6. N.J. residents add 5% sales tax.

Manual cost applicable against price of subsequent
software purchase in any item except for the Osborne
software.

For information and tech queries call

609-599-2146

For phone orders ONLY call toll free

1-800-327-9191
Ext. 676

(Except Florida)

OEMS

Many CDL products are available for licensing to
OEMs. Write to Carl Galletti with your requirements.

* Z80 is a trademark of Zilog

* TRS-80 is a trademark for Radio Shack

* TPM is a trademark of Computer Design Labs. It is not
CP/M*

* CP/M is a trademark of Digital Research

Prices and specifications subject to change without
notice.

DEALER INQUIRIES INVITED.

C BASIC 2

Required for Osborne software. $99.95/$20.

COMPUTER
DESIGN
LABS

is - 18

342 Columbus Avenue
Trenton, N.J. 08629

iS Reader Service index— page 241

Microcomputing, October 1980 153

Tracking Down
The Bus

Answers the question of why some boards
won’t work with your S-IOO system.

Richard A. Rodman
c/o Envo, Inc.

800 Follin Lane
Vienna, VA 22180

T he S-IOO bus has one intrin-
sic characteristic: it’s based
on the timing signals of the 8080
microprocessor. Thus, to adapt
bus, the signals generated by
the 8080 have to be simulat-
ed by the Z-80 CPU circuit de-

sign.

This is not easy. The Z-80 re-
quires only a single clock and
generates much more elegant
control signals, while the 8080
requires a two-phase clock with
12-volt swings.

Engineers have found that the
simplest way to simulate the
two-phase clock on the bus is to
use the 8224 clock generator
chip. While the engineers at
Cromemco did not follow this
route, Ithaca Intersystems did;

theirs is the most popular Z-80
CPU board in use.

Many boards, however, do not
work with this CPU, even in its
latest version. The problem is
related to the S-100 interface
logic, and the phase of clock 2
and clock 1 to the PSYNC signal.
The 8080 CPU generates PSYNC
on the leading edge of clock 2.
Clock 2 makes one high-to-low
transition during PSYNC, and
clock 1 makes a low-to-high
transition.

Peripheral boards use these
relative characteristics in a
number of ways.

Dynamic memory boards use
the high-to-low transition of
clock 2 during PSYNC to latch in
the address, which is stabte at
the time. Examples of this type
are the Processor Technology
16KRA and 32KRA memory
boards.

Other boards, such as the
Solid State Music VB1 and many
static memory boards, use the
low-to-high transition of clock 1
for the same purpose.

Finally, some boards will use

TOP EDGE OF BOARD

Fig. 3. Bottom of board modifi-
cation.

the falling edge of clock 2 and
the rising edge of PSYNC to tog-
gle circuitry for the generation
of wait states. These include the
Screensplitter and Alpha Micro
AM-200 floppy-disk controller.

Why will some of these
boards work as is, others poorly
and most not at all?

Fig. 1 shows the circuitry
used by Ithaca Intersystems to
generate PSYNC. The 02TTL
output of the 8224 is used to
operate the Z-80 clock, whereas
the standard outputs 01 and 02,
powered from a 5-volt supply, are
buffered onto the bus. Note also
that the Z-80 output/MREQ (not
memory request) drives a 74121
monostable to generate the
PSYNC pulse on its falling edge.

A timing diagram of these
signals is given in Fig. 2. Since
the Z-80 outputs / MREQ low on
the falling edge of the clock ap-
plied to it, that PSYNC will make
its low-to-high transition on the
falling edge of 02, rather than
the rising edge. This means that
while 01 will make its required
transition, 02 will not make a
high-to-low transition during
PSYNC.

Since the Z-80 doesn’t use 01,
simply invert 02TTL before it
gets to the Z-80, so that /MREQ
will make PSYNC occur at the
right time.

I wrote Ithaca about this prob-
lem, but they weren’t interested,
so you’ll have to modify your
own board. Refer to Fig. 3 for
details. All mods are done on the
solder side of the board.

1. Remove R6 (330 Q orange-
orange-brown) carefully and
save it.

2. Cut the third trace from the
top on the solder side, right near
U12 where it makes an angle
(see Fig. 3).

3. With U12 at the top, con-
nect the side on the right to U12,
pin 5.

4. Connect the left side (going
to the CPU) to pin 6. The wires
should criss-cross. As with all
PCB mods, use #30 Kynar wire-
wrapping wire or equivalent.

5. Connect R6 between pin 14
and pin 6 of U12.

This completes the modifica-
tion, and all of the boards men-
tioned above should operate
correctly. ■

— n__n__n_

J L

CLOCKS PUT OUT BY 8224
CLOCK GENERATOR 1C.

RESULTING SIGNALS GENERATED
BY Z-80 IN UNMODIFIED
ITHACA INTERSYSTEMS CIRCUIT

SIGNALS GENERATED BY Z-80
> AS A RESULT Or MODIFICATIONS
DESCRIBED IN THIS ARTICLE.

Fig. 2.

154 Microcomputing, October 1980

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156 Microcomputing, October 1980

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is 0 Reader Service index — page 241

Microcomputing, October 1980 157

Dial-up Directory

Meet the father of Forum-80, Bill Abney.

Frank J. Derfler, Jr.
PO Box 691
Herndon, VA 22070

I f you’ve read the Dial-up Directory list-
ings, you’ve seen the title Forum-80. In
previous articles I’ve examined Computer
Bulletin Board Systems Chicago-style, Ap-
ple Bulletin Board Systems by Bill Blue and
two North Star systems. For this issue, I
visited the creator of the Forum-80, Bill
Abney, to find out more about making Radio
Shack’s TRS-80 into an electronic bulle-

tin board and program transfer system.

Bill: “I’m only one deep, Frank. I receive
calls from my Forum-80 operators around
the country and constantly try to help them
with problems. I have almost no time to an-
swer other inquiries. My stack of letters
right now is about four inches deep.”

Microcomputing: “You used a phrase
there, Bill. You said, ‘my operators.’ It has
been said that you have a very strong propri-
etary feeling about Forum-80 systems, de-
spite the fact that each one is run by other
private individuals.”

Bill: “I refer to the Forum-80 network. It is

not a network of stations that is permanent-
ly interconnected, but the interconnection
is there at several levels. The users check
into different systems and carry informa-
tion between them. The system operators
also swap messages between the sys-
tems.

“I feel it is very important to keep compat-
ibility and uniformity between the Forum-80
operations. Some operators would like to
make changes in their systems to provide
unique services, but they can’t do it with the
existing software. The version 2.1 software
has been expanded about as far as it can go
while still maintaining uniformity. There
have been other problems too.”

Microcomputing: “Like what?”

Bill: “Software sharks for one. Bandits
who make very small changes in my soft-
ware and sell it themselves. I stopped put-
ting out any more 2.1 software in December
1979 and fired up a version 3.0 in February
1980. The new version will give the Forum
operators the flexibility to provide all the
special features they like while maintaining
uniformity for the user. Version 3.0 will be
provided to the Forum operators, but they
will not own it. It will be licensed like other
commercial software. New licenses will
cost about $150.”

Microcomputing: “How will you allow
more versatility in the program?”

Bill: “Version 3.0 will allow branching into
special-purpose subroutines, but the sys-
tem will initially come up looking like any
other Forum-80 to the users. Users can then
treat the system as a standard Forum-80 or
move into special uses.”

Forum Augusta, GA

(3.0)

803-279-5392

Forum Boston, MA

(3.0)

617-431-1699

Forum Chicago, IL

(2.5)

312-782-8180

Forum Cleveland, OH

(3.0)

216-486-4176

Forum Dallas, TX

(3.0)

214-288-4859

Forum Denver, CO

(3.0)

303-789-0936

Forum Fairfax, VA

(3.0)

703-978-7561 (Genealogy)

Forum Ft. Lauderdale, FL

(3.0)

305-772-4444

Forum Kansas City, MO

(3.0)

816-861-7040 (H.Q. SYS)

Forum Kansas City, MO

(3.0)

816-931-9316 (Commodities)

Forum Las Vegas, NV

(3.0)

702-873-9491

Forum Memphis, TN

(3.0)

901-276-8196

Forum Memphis, TN

(3.0)

901-362-2222 (Hobbyist)

Forum Mt. Clemens, Ml

(3.0)

313-465-9531 (Medical)

Forum San Francisco, CA

(3.0)

415-348-2139

Forum Tampa, FL

(2.1)

813-223-7688

Forum Union, NJ

(3-0)

201-688-7117

Forum Ventura County, CA

(2.1)

805-484-9904

Forum Wichita, KS

(3.0)

316-746-2078

Forum Wichita Falls, TX

(2.1)

817-855-3916

in honor of our interview with Forum-80 founder, Bill Abney, 1 will limit our system
list this month to Forum systems. Bill has provided this current (as of publication
deadline) list of active Forum-80 systems. The number in parentheses refers to the
version of software in use. Version 3.0 has the most complete set of features.
Some of these numbers may be redundant to previous lists. Some of the most in-
teresting special-user systems are running with the Forum-80 software.

158 Microcomputing , October 1980

Bill Abney, the Forum-80 founding father.
Bill provides a lot of support for his
Forum-80 operators, but wishes he had time
to do more.

Microcomputing: “You mean uses like
family history and medical applications?”
Bill: “Yes. I have heard of a special-
interest system for photographers too.
Some operators may want to provide spe-
cial services, graphics, programs to run,
user codes and many other things. These
submenus can be used by the people they
are intended for, while other, less sophis-
ticated, users see the basic Forum-80 menu
come up in default. I would expect the
operators to contribute submenu software
to the network pool so it can be shared
where appropriate.”

Microcomputing: “Aside from the soft-
ware, what does a person need to set up a
Forum-80?”

Bill: “They need a TRS-80 with 48K of
memory. This means they need the expan-
sion interface. It has to have the RS-232
card installed. They need three disk drives
for version 3.0. With the older version the
third disk was optional, but it is needed in
this version. They also need an automatic
answer modem. This will give the full Forum
capability.”

Microcomputing: “That looks like a $3500
system at retail prices. What kind of modem
do you recommend?”

Bill: “I think the U.S. Robotics auto an-
swer modem is a tremendous piece of
equipment. It is well designed and inter-
faces with the TRS-80 very well.”
Microcomputing: “The Forum-80 in Kan-
sas City (816-861-7040) is referred to as the
‘headquarters.’ Is it a very active system?”
Bill: “This system is more for demonstra-
tion than anything else. It is the only com-
puter I own, and I use it for all the develop-
ment work, so it is on the phone as a forum
at odd hours. However, during the online
hours, the Forum-80 Headquarters System
serves many regular and long-distance us-

ers.”

Microcomputing: “How did you arrive at
the Forum-80 name?”

Bill: “I felt that the term Bulletin Board im-
plied merely a place to post notices. A fo-
rum is more a place of public discussion. In
this view, I hoped the Forum would become
a place where the microcomputer user
could discuss his pursuits and exchange in-
telligence with others. I feel the educational
value is immense, both for the beginners
and the experienced users. The 80 in the
name, of course, came from the TRS-80, but
with the 3.0 system we are attempting to
achieve compatibility with other machines
and prefer to look at it as the ‘Forum of the
80s.’ ”

Microcomputing: “What else would you
like our readers to know, Bill?”

Bill: “That’s easy! Please tell them to use
and read the help commands available on
every system. If they use trial and error
learning to find all of the Forum’s features,
they will be frustrated, will probably miss
something and will keep the system busy
for much longer than it needs to be. If they
send a self-addressed legal-size envelope
with two first-class stamps attached, I will
send them a Forum-80 user’s guide. I would
much rather pay to print up this guide than
have people tie up systems. It is nothing

fancy, but it is useful. I hope they read it.”

Send your large double-stamped self-ad-
dressed envelopes to: Forum-80 Headquar-
ters, 7600 E. 48th Terrace, Kansas City, MO
64129.

The Micro-Connection

Here are two names for you: The Periph-
eral People and Don Stoner. The first name
was new to me, but the second has been fa-
miliar for a long time. Don Stoner is better
known to the amateur radio world as
W6TNS. He has been involved in radio
equipment design and manufacturing at
several different levels. The Peripheral Peo-
ple is the name of Don’s company in Wash-
ington state.

These names are interesting, particularly
to TRS-80 users, because of their new prod-
uct called the Micro-Connection. Basically
a modem, this device connects directly to
the phone line so you don’t need an
acoustic coupler. (Acoustic couplers and
telephone handsets sometimes cause dis-
tortion, and can be the entry point for dis-
ruptive noise.)

This device will interface with all TRS-80
models I, II and III, as well as the TRS-80
Color Computer; any memory size; any type
of BASIC; and with or without an expansion
interface. Previously, a computerist needed

The Micro-Connection modem in operation. It is a small, convenient device with great
capabilities.

Microcomputing, October 1980 159

the expansion interface and had to install
the RS-232 card to use a modem for tele-
communications. This called for a $400
investment before you even got to the
modem price.

The Micro-Connection is selling for $249.
It plugs into the TRS-80 bus connector, or
can plug directly into the screen printer port
of the expansion module.

The Micro-Connection also has a female
RS-232 output connector on the modem.
Thus, a serial printer can print along with
the modem and provide hard copy of every-
thing on the screen, without fancy software.
This provides a port that is separate from
the regular TRS-80 RS-232 card. You can op-
erate the Micro-Connection as just an inter-
face between the TRS-80 and any RS-232
device — it does not have to be operating as
a modem to give RS-232 output. This means
you can run a series printer without the ex-
pansion interface and RS-232 card. Do you
understand why they call it the Micro-Con-
nection?

Finally, since Don is an active amateur ra-
dio operator, the literature for the Micro-
Connection points out that you can use this
device with an amateur radio station to
transmit and receive ASCII. This can be
done with any modem, of course, but the
configuration of the Micro-Connection
makes it easy to get at the audio input and

audio output lines for interconnection to
the radios. Since the FCC made ASCII
transmission legal in March, this has be-
come an very important consideration for
modem users and manufacturers.

For more information on the Micro-Con-
nection, contact The Peripheral People at
PO Box 524, Mercer Island, WA 98040. They
also run their own bulletin board system at
206-723-DATA.

Random Noise

Some users of Novation CAT and other
acoustically coupled modems have written
to say that they have some intermittent
distortion problems that seem to involve
the telephone handset. The cures include
everything from putting cotton in the ear-
piece cup to using strange chants and in-
cantations.

These cures sound like the medieval
treatment for the plague, but there is a little
science behind them. Part of the science in-
volves doing something — anything — to un-
pack the carbon granules in the telephone
mouthpiece. The old-time ham radio opera-
tors used to broadcast with a pencil in one
hand and tap the microphone periodically
to unpack the carbon.

Got a transmission problem with an
acoustically coupled modem? Made sure
the phone is tightly seated and the environ-

ment is free of outside noise and bang the
phone mouthpiece against your palm once
or twice. It might help.

Also, the carbon microphones create a
second harmonic feedback through the
handset back to the earpiece, thereby
creating distortion in the modem input side.
That may explain why cotton around the in-
side of the earpiece sometimes helps. It can
dampen the second harmonic vibration.
Just don’t cover up the sound holes or cut
down on the level of the tones you want.

Novation is coming out with a dynamic
element to replace the carbon one in your
telephone if it becomes a persistent prob-
lem. This element will do away with both
carbon packing and second harmonic reso-
nance.

This is another argument in favor of
direct-coupled modems. They aren’t as por-
table, but they may provide more reliable
operation.

Data Transfer

Send me your data! If you have com-
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computer bulletin board services or other
aspects of data transmission, let me know.
Use the address at the beginning of the arti-
cle or send it to TCB967 on The Source.
Send a stamped envelope if you want a
response to paper mail. ■

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Reader Service index— page 241

Microcomputing, October 1980 161

Reduce Search Time
With an Index

The author shows how you can breeze through file searches
with this Heath H8 program.

LeRoy E. Kolderup
1497 Sugartown Road
Paoli, PA 19301

M icroprocessors are frequently used in
business applications to search long
files for a specific record. Such a search is
usually made by moving the file into main
memory and using a BASIC routine of the
type shown in Listing 1, where a name (N$)
is used as a key to locate a record (M$[K]). A
print of this record supplies the desired in-
formation contained in the remainder of the
record, which might include address, date
of last order and so on.

The limitations imposed by BASIC and by
sequential files make a search through
several hundred records a time-consuming
task that would try anyone’s patience. But
the time can be significantly reduced by us-
ing an index.

A file can be indexed in many ways, but
some methods are elaborate and unsuit-
able for use on a small system with limited
memory. The indexing system described
here uses less than 100 bytes of memory,
can be easily generated and will reduce
search time by a factor of from ten to 20.

In a business application, the principle
key with which a search is made might be
the name of an individual or company. The

records can be arranged in alphabetic order
of the principle key. The index system that
will be described supplies the record num-
ber of the first record that begins with each
letter of the alphabet. This information is
then used to limit the area of search to a
specific portion of the file.

Generating the Index System

The first step in generating this index is
to sort the file, if it is not already in alpha-
betic order. This step need only be repeat-
ed when additional records are added to a
file. For files of any significant length, the
sort technique should be more advanced
than the overused bubble sort to avoid ex-
cessive sorting times. Such techniques as
the Shell-Metzner sort or Hoare’s Quick-
sort have been described in detail and will
not be repeated here (see “Quicksort,”
Microcomputing, April 1979, p. 96).

The second step generates an index that
lists the record number of the first record
that starts each alphabetic character
group. If the file contains records that begin
with the letter A, its index value will, of
course, be 1 . If the first record that has a key
beginning with the letter G is record number
145, then the index for G will be 145. If there
is no record beginning with a particular al-
phabetic character, its index is made equal
to the number of the last record in the file.

A program to generate this index is given
in Listing 2. 1 presume that the file to be in-
dexed is formatted with the keyword at the
beginning of each record, has been sorted
alphabetically and resides on disk. Lines 10
through 80 constitute the input routine to
load the file into memory. This program was
prepared on a Heath H8, and some modifi-
cations may be required for other disk sys-
tems or for a tape system.

The last record in the file is a special rec-
ord that contains two numeric zeros in char-
acter format (00) as the two leading charac-
ters. Note that detection of this pair of zeros
in line 50 serves as a convenient end-of-file
marker. If the file has not been previously in-
dexed, then this character pair should be
appended as the final record before using
the index generator.

Lines 120 through 190 generate the index,
1(A) for A = 1 to 26. Line 140 initially com-
pares the ASCII code of the first character
of the record with the code for the character
A. If they do not compare, no records start
with A, and the index value assigned to 1(1)
is the value of the final record. The next
character in the alphabet is then selected
and the process is repeated. If the compari-
son is true, then 1(1) Is set equal to one in
line 150.

Line 160 selects the next record and
checks for the end-of-file in line 170. Line
180 compares the first character of the rec-
ord with that of the previous record and con-
tinues selecting the next record until a line
beginning with a different character is
reached. The program then goes to the next
alphabetic character and repeats until all
characters of the alphabet have been in-
dexed by assigning the number of the rec-
ord that first begins with each letter of the
alphabet to the index 1(A).

Lines 210 through 240 pack this index in-
to a single string that is structured to re-
quire a minimum of file space and can be

>LIST EXAMPLE. BAS
00120 INPUT "NAME? ";N$

00130 IF N$="ST0P" THEN 190
00140 FOR K=1 TO 400

00150 IF LEFT$(M$<K),LEN(N$) ) : =N$ THEN PRINT H$<K):GOT0 120
00160 NEXT K

00170 PRINT "NO MATCH FOUND"

00180 GOTO 120
00190 END

Listing 1. Typical file search routine.

162 Microcomputing, October 1980

:>LIST INDEXGEN.BAS

00005 REH FILE INPUT ROUTINE

OOOIO DIM M$ ( 400 ) , I ( 26 )

00020 OPEN "TESTFILE" FOR READ AS FILE #1
00030 FOR K=1 TO 400
00040 LINE INPUT H1,;M$(K)

00050 IF LEFT$(H$(K),2)= H 00" THEN 70
00060 NEXT K
00070 CLOSE HI
00080 Z=K-1

00090 REM END OF FILE INPUT
00110 REM BEGIN INDEX GENERATION
00120 K= 1

00130 FOR A=1 TO 26

00135 REM CHECK FOR MATCH OF 1ST CHARACTER OF RECORD AND ALPHA CHARACTER
00140 IF ASC(MKK) )<>A+64 THEN I(A) = Z:GOTO 190
00145 REM ASSIGN RECORD NO. AS INDEX VALUE
00150 I(A)=K

00155 REM SELECT NEXT RECORD, CHECK FOR END OF FILE
00160 K=K+1

00170 IF LEFT$(M$(K) ,2)="00 M THEN 190

00175 REM IF 1ST CHARACTER OF RECORD MATCHES THAT OF PRECEEDING RECORD
00177 REM THEN NEXT RECORD

00180 IF ASC(M$(K) )=ASC(M$(K-1 ) ) THEN 160
00190 NEXT A

00200 REM GENERATE INDEX STRING AND APPEND TO FILE
00210 I$="00"

00220 FOR A=1 TO 26

00230 I$=I$+LEFT$(RIGHTi(" "+STR$ (1(A)), 4), 3)

00240 NEXT A
00250 MKZ + 1 ) = Ii

00260 REM END OF INDEX GENERATION

00290 REM URITE FILE UITH INDEX APPENDED BACK TO DISK
00300 OPEN •'TESTFILE*' FOR URITE AS FILE HI
00310 FOR K S 1 TO Z+1
00320 PRINT HI ,M$(K)

00330 NEXT K
00340 CLOSE HI
00350 END
>

Listing 2. Program to generate a file index.

’♦PRINT I*

OO 1 16 58 941061181 4517338721 1 21 723825928028929238731 0328358387387367387382387

Listing 3. Format of index string.

easily decoded in the search routine. This
string begins with the character pair 00 and
continues with three digits allocated for
each index entry. Line 230 converts the in-
dex value for each 1(A) to character format,
strips the trailing zero and either adds or
strips leading zeros to make all entries have
a length of three characters. (A file with
more than 999 records will require this rou-
tine to be modified to allow for four charac-
ters.) These values are then strung together
to form the index string.

Listing 3 illustrates the format of the in-
dex string for a typical file. In this example,
the first record in the file begins with A, rec-
ord 16 is the first record beginning with B,
record 58 with C and so on. No records
begin with the letters I, Q, U, V, X and Z;
therefore, these letters are indexed to 387,
the last record in the file. Line 250 appends
this index string to the end of the file. Lines
300 through 340 write the file with the ap-

pended index back to disk.

Searching the Index

The indexed file is now ready for a rapid
search. Changes to a record (other than the
first character of the keyword) or deletion of
a record can be made without requiring the
generation of a new index.

A typical program for searching the in-
dexed file is shown in Listing 4. Lines 10
through 70 contain the input routine to load
the file together with the index string into
memory. Lines 80 through 110 decode the
index string into 26 index values for 1(A).
These values are then used in line 140 of the
search routine to confine the search to
those records that begin with the same
character as the key. If no records that start
with this character are present, the search
is indexed to the end of the file and the “NO
MATCH FOUND” message is immediately
displayed.

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i/ 0 Reader Service index— page 241

Microcomputing, October 1980 163

The program was tested using a file con-
taining 387 records. The index generation
process (lines 120 through 250, Listing 2)
was completed in 90 seconds after the file
was loaded into memory. (File load and
dump time will vary with record lengths and
distribution of a file on the disk sectors.)

The file was then searched for several
records scattered throughout, using the
last name as a key and printing out the com-
plete record as the response. I used the pro-
gram contained in Listing 4. The response
times varied from one to six seconds, with
an average of 2.6 seconds.

I repeated the test without the benefit of
an index by changing line 140 to read FOR
K = 1 TO 400 and deleting lines 80 through
110 from the program in Listing 4. The file
was searched for the same records as in the
previous test. In this case, the response
times varied from three to 66 seconds. As
you would expect, the time for any given
record was roughly proportional to the rec-
ord number. The average time of 38 sec-
onds was about 15 times longer than that
required with an index.

The above indexing scheme is one of sev-
eral possible methods of using an index.
This one requires little additional memory,
has a simple index generation program and
requires only a few additional lines to the
search routine. It is directly applicable to al-
most any database file and can be adapted
with minor modifications to handle a case
where the keyword is located at other than
the beginning of a record. It can be used to
quickly locate records for both display and
update purposes.

Application of this technique to a file
with as few as 100 records will pay off in re-
duced time to locate specific records for
display, update or other processing. For
larger files, the time saved is significant,
and efficient data processing demands the
use of an index. ■

>LIST QSEARCH.BAS

00005 REM FILE INPUT ROUTINE

00010 DIM Ml (400 ) , I < 26)

00020 OPEN "TESTFILE" FOR READ AS FILE #1
00030 FOR K=1 TO 400
00040 LINE INPUT #1,;M$(K)

00050 IF LEFT$(M$(K) ,2)="00" THEN 70
00060 NEXT K
00070 CLOSE N1

00075 REM DECODE INDEX STRING
00080 I$=M1(K)

00090 FOR A=1 TO 26

00100 I ( A)=VAL(HID4( 1$ r 3*A f 3 ) )

00110 NEXT A

00115 REM FILE SEARCH ROUTINE

00120 INPUT "NAME? "JN1

00130 IF N$="ST0P" THEN 190

00140 FOR K = I<ASC(N$)-64) TO I(ASC(N$ )-<63 )

00150 IF LEFT$(M*(K),LEN<N$))=N$ THEN PRINT N$(K):G0T0 120
00160 NEXT K

00170 PRINT "NO MATCH FOUND"

00180 GOTO 120
00190 END

>

Listing 4. Search program for an indexed file.

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164 Microcomputing , October 1980

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Microcomputing, October 1980 165

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range and bearing to a target, and tell
you when to attack. And, if things should
get a little too hot, you have an ejection
seat command for egress.

For a carrier-based landing, you’ll
have to deploy your tail hook. For a land-
based landing, you’ll need reverse thrust
and your drag chute.

After you’ve flown a few missions with
the Jet Fighter Pilot package, you’ll
know you’ve earned your wings.

Order No. 01 59R $14.95

Cosmic Patrol

WARNING: PLAYERS OF THIS GAME
SHOULD BE PREPARED FOR A STATE
OF REALISM HITHERTO
UNAVAILABLE ON THE TRS-80

The Cosmic Patrol program puts you
in the command chair of a small in-
terstellar patrol craft. Your mission is to
defeat Terran space and prey on the
Quelon supply ships which carry essen-
tial parts and lubrificants for that im-
placably hostile robotic force. The drone
freighters are fairly easy pickings for the
accomplished starship pilot, but beware
of the 1-Fighter escorts. They’re armed,
fast and piloted by intelligent robots
linked to battle computers. They never
miss.

The Cosmic Patrol program is not just
another search and destroy game. With
its fast, real-time action, impressive
sound option and superb graphics, this
machine-language program is the best
of its genre.

Don’t keep putting quarter after
quarter into arcade games or spending
big bucks for video games cartridges.
Get Cosmic Patrol from Instant Soft-
ware— and get the best for less!

Order No. 0223R $14.95

Battleground

It is late 1944, and the Allied Forces
are sweeping toward Berlin. As General
in command of your sector, you study
the map. At your command, are tanks,
planes, artillery, infantry, engineers and
vehicles— an awesome array of fighting
men and the machines of war. From In-
telligence reports you know that the
enemy General is a shrewd tactician, not
to be under-estimated. It will take plann-
ing and strategy to outwit this wily old
campaigner.

The battle map of your sector will fill
with markers, each showing the deploy-
ment of your forces. You and another
player will slip into the roles of opposing
German and American commanders as
yet another battle unfolds.

Battleground allows you to ex-
perience the awesome responsibility of
a battle-area command. It will be up to
you to deploy your tanks, planes,
vehicles, weapons and men. On your
shoulders rests the decision, whether to
call for direct artillery gunfire, or to order
your planes into the air. You will con
stantly be watching for an enemy air-
drop, always carefully maneuvering your
forces.

The stark reality of World War II
comes alive in Battleground.

Order No. 01 41 R $9.95

TO ORDER: Look for these programs at the
dealer nearest you (see list of dealers on page
199). If your store doesn't stock Instant
Software send your order with payment to:
Instant Software
Order Dept,

Peterborough, N.H, 03458
(Add $1.00 for handling) or call toll-free
1-800-258-5473 (VISA, MC and AMEX ac-
cepted).

Instant Software

Prices subject to change without notice.

PETERBOROUGH, N.H. 03458
603-924-7296

166 Microcomputing, October 1980

Ask for Instant Software at a computer store near you.

Alabama

Anderson Computers
3156 University Dr., Huntsville
Computerland of Huntsville
3020 University Dr., Huntsville
OlensKy Bros.

3763 Airport Blvd., Mobile

Arizona

Professional Data Systems
4506-A N. 16th St.. Phoenix
Millets TV & Radio
621 East Broadway, Mesa

California

AMCO Elect. Supply
635 E. Arrow Hwy., Azusa
Byte Shop

8038 Clairmont Mesa Blvd., San Diego
Byte Shop

123 E. Yorba Linda, Placentia
Byte Shop of Mt. View
1415 West El Camino Real, Mt. View
Byte Shop of Sacramento
6041 Greenback Ln., Citrus Heights
Capital Computer Systems
3396 El Camino Ave., Sacramento
Computers Made Easy
819 East Ave. 0-9, Palmdale
Computer Store of San Leandro
701 MacArthur Blvd., San Leandro
Computer World

6791 Westminster Ave., Westminster
Computerland

16720 S. Hawthorne, Lawndale

Computerland of W. LA

6840 La Cienega Blvd., Inglewood

Coast Electronics

31 18 No. Main St., Morro Bay

Computerland

24001 via Fabricante No 904, Mission Viejo

Computer Mart of California

315 Diamond Bar Blvd., Diamond Bar

Electronic Systems

4883 Tonino, San Jose

Hobbi-tronics

1378 So. Bascom Ave., San Jose
Hobby World

19511 Business Ctr. Dr., Unit 6. Borthridge
Huntington Computing
2020 Charles St., Corcoran
I.C.E. House Inc.

398 North E. St.. San Bernardino
Jade Computer Products
4901 W. Rosecrans, Hawthorne
Malibu Microcomputing
23910A Deville Way. Malibu
Marfam Co.

6351 Almaden Rd., San Jose
Opamp/Technical Books
1033 N. Sycamore Ave., Los Angeles
PC Computers

10166 San Pablo Ave., El Cerrito
Q.l. Computers, Inc.

15818 Hawthorne Blvd., Lawndale

Radio Shack Dealer

8250 Mira Mesa Blvd., San Diego

Radio Shack Dealer

50 N. Cabrillo Hwy., Half Moon Bay

Santa Rosa Computer Center

604 7th St.. Santa Rosa

Silver Spur Elect. Comm.

13552 Central Ave., Chino

The Computer Store

820 Broadway, Santa Monica

Colorado

Colorado Computer Systems
311 W. 74th Ave., Westminster
Computerland of North Denver
8749 Wadsworth Blvd., Arvada
Computer Shack
1635 South Prairie, Pueblo
Software Gourmet
1111 S. Pearl St., Denver
The Computer Store
2300 Welton St., Denver

Connecticut

American Business Computers
454 Thames St., Groton
Computerlab

130 Jefferson, New London

Computerland

1700 Post Rd., Fairfield

Computerland

60 Skiff St., Hamden

Computer Works

1439 Post Rd. E., Liberty Plaza, Westport
Instructional Systems Computers
807 Hartford Rd., Manchester
Technology Systems
208 Greenwood Ave., Bethel

D.C.

The Program Store

4200 Wisconsin Ave., N.W., Washington. D C.

Florida

Al Personal Computer

178 Oxford Rd., Fern Park

AMF Electronics

11 146 N. 30th St., Tampa

Boyd-Ebert Corporation

1328 West 15th St., Panama City

Computer Center

6578 Central Ave., St. Petersburg

Computer Junction

5450 So. State Rd. 7, Ft. Lauderdale

Computerland

7374 S. Tamiami Trail, Sarasota

Computerland of Ft. Lauderdale

3963 N. Federal Hwy., Ft. Lauderdale

Computerland of Jacksonville

2777-6 University Blvd. W. Jacksonville

Computerland of Tampa

1520 E. Fowler Ave.. Tampa

Computerland of West Palm Beach

4275 Okeechobee Blvd., West Palm Beach

Computer Shack

3336 Beach Blvd., Jacksonville

Computer System Resources Inc.

3222 S.W. 35th Blvd., Gainesville

Curtis Waters Enterprises

236 Talbot Ave.. Melbourne

Heath Kit Electronic

4705 W. 16th Ave. Center, Hialeah

HIS Computermation

1295 Cypress Ave., Melbourne

Ukatan Computer Store

Airport Rd., Destin

Williams Radio & TV Inc.

2062 Liberty St., Jacksonville
Your Basic Computer Store
971 Seaway Dr., Ft. Pierce
Georgia

Atlanta Computer Mart
Atlanta

Computerland of Atlanta
2423 Cobb Parkway, Smyrna
Micro Computer Systems
3104 E. Shadowlawn N.E., Atlanta

Hawaii

Computerland of Hawaii
567 N. Federal Hwy., Honolulu
Radio Shack Assoc. Store
1712 S. King St., Honolulu

Idaho

Electronic Specialists
8411 Fairview Ave., Boise

Illinois

Computerland

4507 North Sterling. Peoria

Computerland

9511 N. Milwaukee Ave., Niles
Computer Station
3659 Nameoki Rd., Granite City
Garcia & Associates

203 No. Wabash Ave., Suite 1510, Chicago
Midwest Micro Computers, Inc.

708 S. Main St.. Lombard

Indiana

Computer Center of South Bend
51591 US 31 North, South Bend
Data Domain

221 W. Dodds, Bloomington
Fall Creek Electronics Store
732 Center St., Pendleton

Iowa

Memory Bank

1721 Grant St., Bettenborf

Kansas

Central Kansas Computers
6 S. Broadway. Herington

Maine

Maine Computronics
Intown Plaza. Bangor
Mid Maine Computer Co.

158 Turner St., Auburn
Radio Shack

315 Main Mall Rd., So. Portland

Maryland

Computer Age

9433 Georgia Ave., Silver Springs

Jack Fives Electronics

4608 Debilen Circle, Pikesvllle

The Comm Center

9624 Ft. Meade Rd., Laurel

Massachusetts

ComputerCity

175 Main St., Charlestown

ComputerCity

50 Worcester Rd., Framingham

Computerland of Boston
214 Worcester Rd., Wellesley
Computer Packages Unlimited
342 Boston Turnpike, Shrewsbury
Land of Electronics
1127 Western Ave., Lynn
Lighthouse Computer Software

14 Fall River Ave., Rehobath
Mark Gordon Computers

15 Kenwood St., Cambridge
New England Electronics Co.

679 Highland Ave., Needham
Small Business System Group
Main St., Dunstable

The Computer Store
120 Cambridge St., Burlington
Tufts Radio & Electronics
206 Mystic Ave., Medford
Michigan

Computer Center

28251 Ford Rd., Garden City

Computer Connections

38437 Grand River, Farmington Hills

Computerland of Grand Rapids

2927 28th St. S.E., Kentwood

Computerland of Southfield

29673 Northwestern Hwy., Southfield

Computer Mart

560 W. 14 Mile Rd., Clawson

Computer Room

455 E. Michigan Ave., Kalamazoo
Computronix Corp.

423 S. Saginaw Rd., Midland
Hobby House

1035 W. Territorial Rd., Battle Creek
Main Systems Inc.

1161 No. Ballenger Hwy., Flint

The Alternate Source

1806 Ada, Lansing

The Eight Bit Corner

722 Evanston Ave., Muskegon

TRI Country Electronics & Sound Center

1537 North Leroy, Fenton

Ye Olde Teacher Shoppe

1823 Witmyre St , Ypsilanti

Minnesota

Computerland of Hopkins
11319 Hwy F.. Hopkins
Digital Den
Burnsville Center
Minnesota Software Inc.

5422 Fisher St., White Bear Lake
Zim Computers

5717 Xerxes Ave., N. Brooklin Center

Mississippi

Dyer's, Inc.

200 E. Main St., West Point
Softwarehouse
816 Foley St.. Jackson
W. Vernon Foster Inc.

816 Foley St.. Jackson

Missouri

Century Next Computers

1001 E. Walnut, Columbia

Comp-U-Trs Software Center

51 Florissant Oaks Shopping Center, Florissant

Software Shack

16501 Greenwald Court, Belton

Montana

Intermountain Computer

529 So. 9th St., Livingston

Personal Computer

121 Red Oak Dr., Carl Junction

The Computer Store

1216 16th St. W. #35, Billings

Nebraska

Computerland of Omaha
11031 Elm St., Omaha
Midwest Computer Co. Inc.

8625 I St., Omaha
Midwest Computer Co. Inc.

4442 S. 84th St., Omaha
Midwest Computer Co. Inc.

4403 S. 87th St., Omaha
Scottsbluff Typewriters Inc.

1824 Broadway, Scottsbluff

Nevada

Century 23

4566 Spring Mountain Rd.. Las Vegas

New Hampshire

Bitsnbytes Computer Center

568 Pleasant St., Concord

ComputerCity

1525 S. Willow, Manchester

Paul s TV

Main St., Fremont

Portsmouth Computer Center

31 Raynes Ave., Portsmouth

Radio Shack Assoc. Store
Fairbanks Plaza, Keene
Sturdivant and Dunn
124 Washington St., Conway

New Jersey

Abe's TV Sales & Service

College Town Shopping Center, Glassboro

Computer Corner of NJ

439 Rte. #23, Pompton Plains

Computer Encounter

2 Nassau St.. Princeton

Computerland

35 Plaza Rte. #4, W. Paramus
Computer Mart of NJ
501 Rte. 27, Iselin
Crowley's

Rd. #3, Whitehouse Station
Dave’s Electronics
Pennsville Shopping Ctr., Pennsville
GHB Enterprises Inc.

Rte. 38, Rudderaw Ave., Mapleshade
Lashen Electronics Inc.

21 Broadway, Denville
Personal Computing Inc.

51 Central Sq., Linwood
Radio Shack/J&J Electronic
Mansfield Shopping Ctr.

Rt. 57 Allen Rd., Hackettstown
The Bargain Brothers
Glen Roc Shopping Center
216 Scotch Road, Trenton
The Computer Emporium
Bldg. 103, Avenues of Commerce
2428 Rte. 38. Cherry Hill

New Mexico

Autel Electronics Co.

232 Wisconsin N.E., Albuquerque
South West Computer Center
121 Wyatt Drive. Suite 7, Las Cruces
Thomas E. Carr Jeweler
1300A Tenth St., Alamogordo

New York

Aristo Craft

314 Fifth Ave., NYC

Berliner Computer Center

t02 Jericho Turnpk, New Hyde Park

Bits & Bytes

2800 Straight Rd., Fredonia
Computer Corner
200 Hamilton Ave.. White Plains
Computer Era Corp.

1570 3rd Ave., New York
Computer Factory
485 Lexington Ave., NYC
Computer House, Inc.

721 Atlantic Ave., Rochester
Computerland of Nassau
79 Westbury Ave., Carle Place
Computerland of New York City
58 W. 44th SI.. New York
Computer World

519 Boston Post Rd., Port Chester
Comtek Electronics, Inc.

2666 Coney Island Ave., Brooklyn
Comtek Electronics, Inc.

Staten Island Mall
Store 220A, Staten Island
Dlgibyte Systems Corp.

31 E. 31st St.. New York
80-Microcomputer Services
118 Masten Ave., Cohoes
Home Computer Center
671 Monroe Ave., Rochester
Mr. Computer

Imp. Plaza, Rte. 9, Wappingers Falls
Softron Systems

308 Columbia Turnpike, Rensselaer
The Computer Tree Inc.

409 Hooper Rd., Endwell
Upstate Computer Shop
629 French Rd.. Campus Plaza, New Hartford

North Carolina

Byte Shop of Raleigh

1213 Hillsborough St., Raleigh

Sound Mill

Slocum Shopping Ctr., Havelock

Ohio

Altair Business Systems, Inc.

5252 North Dixie Dr., Dayton
Astro Video Electronics
504 E. Main St., Lancaster
Cincinnati Computer Store
4816 Interstate Dr., Cincinnati
Computerland
4579 Great Northern Blvd.,

N. Olmstead
Computerland

6429 Busch Blvd., Columbus
Computerland

1288 Som Rd., Mayfield Heights
Computer Store of Toledo
18 Hillwyck Dr., Toledo
Forbees Microsystems Inc.

35 N. Broad, Fairborn
Microcomputer Center
7900 Paragon Rd.. Dayton
Micro-Mini Computer World
74 Robinwood, Columbus
21st Century Shop
16 Convention Way. Cincinnati
Universal Amateur Radio, Inc.

1280 Aida Dr., Columbus

Oklahoma

Sounds, Etc.

Hyw. 33, Watonga
Vern Street Products
114 W. Taft St., Sapjlpa

tS 40

Instant Software

PETERBOROUGH, NEW HAMPSHIRE 03458

Oregon

Computerland of Portland
12020 S.W. Main St., Tigard
Computer Pathways Unlimited, Inc.
2151 Davcor St. S.E., Salem
TRS-80 Products Ltd.

3520 S.E. Vineyard Rd., Portland

Pennsylvania

Artco Elect.

302 Wyoming Ave., Kingston
Artco Elect.

Back Mountain Shopping Center,

Shavertown

Audio Mart

518 Fifth Ave., New Brighton
Computer Workshoppe
3848 William Penn Hwy, Monroeville
Computerland of Harrisburg
4644 Carlisle Pike. Mechanicsburg
Computerland of Pittsburgh
5499 William Flynn Hwy., Gibsonia
Erie Computer Co.

2127 West 8th St.. Erie
Mighty Byte Computer Center
537 Easton Rd., Horsham
Personal Computer Corp.

24-26 West Lancaster Ave., Paoli
Personal Computer Corp.

Frazer Mall, Lancaster Ave., Frazer

Rhode Island

Computer City

165 Angell St., Providence

Digital World, Inc.

329 Bald Hill Rd., Warwick

South Dakota

CB Radio Shack

21st and Broadway, Yankton

Tennessee

ACS

1 100 8th Ave. So., Nashville
Computerlab

671 S. Menden Hall Rd.. Memphis
H & H Electronics Inc.

509 N. Jackson St., Tullahoma

Texas

Computer Port
2142 N. Collins. Arlington
Houston Computer Tech
5313 Bissonel, Bellarie
Interactive Computer
7620 Dashwood, Houston
K.A. Elect.

9090 Stemmons Frwy., Dallas
Pan American Elect. Inc.

1117 Conway, Mission

Radio Shack Dealer

21969 Katy Freeway, Katy

The Compute Shop

6353 Camp Bowie Blvd., Ft. Worth

Waghalter Books Inc.

3 Greenway Plaza E., Houston

Utah

DC Computer Co.

191 1 West 70 South, Provo

Quality Technology

470 E. 2nd So., Salt Lake City

Virginia

Computer Works
Rte. 6, Box 65A, Harrisonburg
Home Computer Center
2927 Virginia Beach Blvd.

Virginia Beach
Southside Radio Comm.

135 Pickwick Ave., Colonial Heights

Washington

American Mercantile Co. Inc.

2418 1st Ave. S., Seattle
Byte Shop of Bellevue
14701 N.E. 20th St.. Bellevue
Computer Connection Inc.

3100 NW Bucklin Hill Rd., Silverdale
Computerland of South King Co.

1500 S. 336 St., Suite 12, Federal Way

Personal Computers

S 104 Freva, Spokane

Ye Old Computer Shop

1301 G. Washington, Richland

West Virginia

The Computer Corner Inc.

22 Beechurst Ave., Morgantown

The Computer Store

Municipal Parking Bldg., Charleston

Wisconsin

Byte Shop Of Milwaukee

6019 West Layton Ave., Greenfield

Computerland

690 S. Whitney Way, Madison
Computerworld

3015 W. Wisconsin Ave., Appleton
Magic Lantern Computed
3313 University Ave., Madison
Petted Microsystems
4265 W. Loomis Rd., Milwaukee

Wyoming

Computer Concepts
1104 Logan Ave., Cheyenne

Puerto Rico

The Microcomputer Store
1568 Ave. Jesus T. Pinero
Caparra Terrace

Canada

CANADIAN DISTRIBUTORS:

Micron Distributing

409 Queen St., W. Toronto, Ont.

M5V 2A5

Microcomputing, October 1980 167

Video HARDCOPY
For CP/M

These machine-language programs give you printing power at the touch of a key.

ccoo *

SCRN

EQU

0CC00H ; VI DEO SCREEN ADDRESS

0100

0R6

1 00H

0100 C5

PUSH

B

JSAVE REGS

0101 E5

PUSH

H

0102 2100CC

LXI

H,SCRN ; SCREEN ADDRESS

0105 7E

VPI :

H0V

A,H {LOOK FOR FIRST

0106 FE20

CPI

' ' {NON-BLANK LINE.

0108 C20F01

JNZ

VP2

01 0B 23

INX

H

010C C30501

JMP

VPI

01 OF 7D

VP2:

NOV

A,L

0110 E6C0

ANI

1 1 OOOOOOB {SET TO LINE BEGINNING

0112 6F

NOV

L, A

0113 7D

VP3:

NOV

A,L JPRINT REST OF SCREEN

01 14 E63F

ANI

001 11 11 IB ;CHECK END OF LINE

0116 C22F01

JNZ

VP4

011? CD4101

CALL

CRLF

011C E5

VPS:

PUSH

H ; CHECK FOR REST OF

01 1 D 7E

VP6:

NOV

A,M ;SCREEN BLANK

01 IE FE20

CPI

' '

0120 C22E01

JNZ

VP7

0123 23

INX

H

0124 7C

MOV

A,H

0125 FEB0

CPI

0D0H ;END OF SCREEN 7

0127 C21D01

JNZ

VP6 ;not YET.

012A El

POP

H ; RESTORE HL REGISTERS

012B C33D01

JNP

VP8 {RETURN TO CP/M. NO MORE TO PRINT

012E El

VP7:

POP

H {RESTORE HL REGISTERS

012F 4E

VP4:

NOV

C,N

0130 CD4C01

CALL

PRINTER

0133 23

INX

H

0134 7C

NOV

A,H

0135 FED0

CPI

ODOH

0137 C21301

JNZ

VP3

013A CD4101

CALL

CRLF

01 3D El

VP8:

POP

H {RESTORE REGS

013E Cl

POP

B

013F C7

RST

0 {RETURN TO CP/N

0140 C9

RET

0141 0E0D

CRLF

MVI

C.ODH {CR

0143 CD4C01

CALL

PRINTER

0146 0E0A

NVI

C,0AH {LF

0148 CD4C01

CALL

PRINTER

014B C?

RET

014C 3A0AFE

PRINTER:

LDA OFEOOH+OAH

014F E601

ANI 01

0151 CA4C01

JZ PRINTER

0154 7?

MOV A, C

0155 3202FE

STA 0FE0OH+2

0158 C9

RET

015?

END

Listing 1. Video HARDCOPY routine.

Glenn Stok
PO Box 501
Woodside NY 11377

H ow often have you wanted
to keep a screen of infor-
mation permanently? This de-
sire has occurred to me many
times. So I decided to add a
hard-copy feature to my CP/M
system.

In this article I will explain the
method, show you the source
listing and explain how to incor-
porate it into your CP/M system
or your monitor. The only hard-
ware requirement is that you
have a memory-mapped video
display and a printer. If you
don’t have CP/M, you can still
use my HARDCOPY routine by
making it part of your monitor
(see Listing 1).

If you have a Z-80 CPU, you
may find Listing 2 helpful. It is
the same HARDCOPY routine
written in Z-80 code. I have re-
stricted this to relative address-
ing so it is relocatable. All you
have to do is patch the machine
code of Listing 2 anywhere in
your monitor and patch branches

to and from it for I/O. The CALL
to your PRINT routine has to be
patched in three places. Make
sure that you correct the ad-
dress in the CALL CRLF instruc-
tions (the Z-80 does not have rel-
ative addressable CALL instruc-
tions). Listing 1 is entirely in
8080 code, so it will run on either
CPU.

Adding Hard Copy

We don’t want the request for
a hard copy to change the
screen. Since we want to copy
the screen, a command that
echoes to the screen will be
messy. We also want to have the
option of making a hard copy
even when running another pro-
gram. As long as it looks at the
keyboard once in a while, this
can be done. This is feasible if
all I/O goes through CP/M or
your monitor. In this case, we
are only concerned about I/O
with the keyboard.

With this situation we can
have the “keyboard read” rou-
tine check for a control key. If it
is not the proper key, then pro-
cess normally. If it is the key that

168 Microcomputing, October 1980

we have chosen for a hard-copy
request, then the logic will
branch to the HARDCOPY rou-
tine before returning to the call-
ing program.

If you have CP/M and under-
stand the workings of your
CBIOS (the Basic I/O Section,
Converted for your system), you
may be saying, “But I don’t have
enough room at the top to add a
routine to my CBIOS!”

Well, yes you do! And here is
how to get more room: Move the
entire CP/M system down one
kilobyte with your MOVCPM
command.

For instance, say you have
24 K. Use EDIT to change the
EQU for system size in both your
CBIOS and your boot loader to
23K. After you add the HARD-
COPY routine to your CBIOS, as-
semble both the boot loader and
the CBIOS. Then follow your nor-
mal procedures with your MOV-
CPM command and SYSGEN to
create a new version for 23K
with hard-copy capabilities.

If you only have a 16K system,
you can’t SYSGEN a 15K system
because 16K is the minimum for
CP/M. But try assembling your
CBIOS at 16K with the HARD-
COPY routine in it. Maybe you
will not go beyond your avail-
able RAM (i.e., address 3FFF). If
you are close, then maybe you
can cut some bytes by changing
some logic of other parts of your
CBIOS.

Source Listing

The source listing of Listing 3

Listing 3. CBIOS source listing.

001? =

MSI ZE

EQU

23

;SIZE OF

OPERATING SYSTEM IN KILOBYTES

F 300 =

CONTROLLER

EQU

0F80QH

FCOO *

BUFF

EQU

CONTROLLERMOOH

5A00 =

LOCATION

EQU

MS I ZE * 1 0

24-512

;0RG LOCATION FOR THE CBIOS

5AOO

0RG

LOCATION

; BASE OF

BIOS IN 23K SYSTEM

0003 =

I0BYTE

EQU

0003H

; I0BYTE

FOR 1/0 CONTROL

< SECTION NOT SHOWN >

1C00

CBASE

EQU

(HSIZE- 16)*1024

;BIAS FOR SYSTE MS GREATER THAN

4500

=

CPM B

EQU

CBASE+2900H

4006

BOOS

EQU

CBASE+31 06H

4480

=

CCPH

EQU

CPHB-1 28

1500

=

CP ML

EQU

4-CPHB

5 A00

C3125B

JHP

COLDBOOT

5A03

C3B95A

EB00T:

JNP

UB00T

5A06

C3555B

JHP

CONSTAT

5A09

C3625B

JHP

C0NIN

5A0C

C3725C

JHP

C0N0UT

5 A0F

C37B5B

JHP

LIST

5 A 1 2

C3835B

JHP

PRINTER

5 A 1 5

C3955B

JHP

READER

5A1 8

C32D5A

JHP

H0ME1

; HOME

5 At B

C3335A

JHP

TEHPSELDSK

JSELDSK

5A1E

C3515A

JHP

SETTRK1

; SETTRK

5A21

C30CF8

JNP

SETSEC

; SETSEC

5A24

C30FF8

JHP

SETDHA

; SETDHA

5A27

C3985B

JHP

READ

;diskread

5A2A

C3B75B

JHP

URITE

JDISKURITE

< SECTION NOT SHOUN >

COLDBOQT: ;D0 THIS ONLY ON COLD START

5B1 2

3E09

HVI

A,00001001 B

; ASSIGN INITIAL

5B1 4

320300

STA

I0BYTE

5B17

AF

XRA

A

5B1 8

D3C8

OUT

0C8H

JINIT.

SCREEN

5B1 A

CDAA5C

CALL

CLRCRT

;CLEAR

THE SCREEN

5 BID

211 15D

LXI

H, SIGMON

5B20

CD185C

CALL

PRHSG

; P R I NT

SIGN0N MESSAGE

BOOT:

< SECTION NOT SHOUN >

5 B52

C30045

JHP

CP M B

C0NIN

ROUTINE CHECKS FOR FUNCTION KEYS

IF NOT

A FUNCTION, THEN

IT RETURNS THE

KEY IN

REGISTER

'A'.

5B62

CD555B (

:0NIN:

CALL

CONSTAT

5B65

CA625B

JZ

C0NIN

5B68

3A02FE

LDA

URC0NT +2

5B6B

E67F

ANI

7FH

Listing 2. HARDCOPY routine in Z-80 code.

0125

0126

El

180E

POP

JHPR

H

VP8

; RESTORE HL REGISTERS
{RETURN TO CP/H.

{NO MORE TO PRINT

ADDRESSED AT HEX 100 FOR STAND ALONE

0128

El

VP7:

POP

H

{RESTORE HL REGISTERS

TEST

UNDER CP/N.

0129

4E

VP4:

NOV

C.N

012A

CD 0145

CALL

PRINT

ccoo

SCRN

=

OCCOOH ; VIDEO SCREEN ADDRESS

012D

23

INX

H

. PADS ; CREATE INTEL HEX FILE

01 2E

7C

NOV

A,H

0100

.L0C

1 00H

012F

FED0

CPI

ODOH

0100

C5

PUSH

B ; SAVE REGS

0131

20DE

JRNZ

VP3

0101

E5

PUSH

H

0133

CD 013A

CALL

CRLF

0102

21 CCOO

LXI

H f SCRN ; SCREEN ADDRESS

0136

El

VP8:

POP

H

{RESTORE REGS

0105

7E

VP 1 :

NOV

A,H ; LOOK FOR FIRST

0137

Cl

POP

8

0106

FE20

CPI

' ' ;non-blank LINE.

0138

C7

RST

O

{RETURN TO CP/H

0108

2003

JRNZ

VP2

0139

C9

RET

01 0A

23

I NX

H

013A

0E0D

CRLF:

NVI

C,0DH

{CR

01 OB

1 8F8

JHPR

VP1

013C

CD 0145

CALL

PRINT

01 0D

7D

VP2:

H0V

A,L

01 3F

0E0A

NVI

C,OAH

;lf

010E

E6C0

ANI

1 1 OOOOOOB {SET TO LINE BEGIN

0141

CP 0145

CALL

PRINT

0110

6F

NOV

L, A

0145

3A FE0A

PRINT

: LDA

0FE00H+OAH

0111

7D

VP3:

NOV

A,L {PRINT REST OF SCREEN

0148

E601

ANI

01

0112

E63F

ANI

001111118 ; CHECK END OF LINE

014A

28F9

JRZ

PRINT

0114

2013

JRNZ

VP4

014C

79

NOV

A,C

0116

CD 0 1 3 A

CALL

CRLF

014D

32 FE02

STA

OFEOOH+2

0119

E5

VPS:

PUSH

H ;CHECK FOR REST OF

0150

C9

RET

01 1 A

7E

VP6:

NOV

A,N ;SCREEN BLANK

.END

0118

FE20

CPI

' '

01 ID

2009

JRNZ

VP7

CRLF

01 3A

PRINT

0145

SCRN

CCOO

01 IF

23

INX

H

VP 1

0105

VP2

01 0D

VP3

0111

0120

7C

H0V

A,H

VP4

0129

VP5

0119

VP6

01 1 A

0121

FED0

CPI

0D0H ; END OF SCREEN?

VP7

0128

VP8

0136

. BLNK . 0000:03 X

0123

20F5

JRNZ

VP6 ;not YET.

.DATA.

0000* X

.PROG.

0000'

X

Microcomputing, October 1980 169

Listing 3 continued.

5B6D

FE60

CPI

;tab key

5B6F

C2755B

JNZ

MAYBHARD

5 B? 2

3E09

MVI

A, 09 ; TAB CODE

5B74

C9

RET

5B75

FE7E

MAYBHARD:

CPI

7EH JHARD COPY KEY

5B77

CO

RNZ

5B78

C3255C

JMP

HARDCOPY JG0 DO HARDCOPY

; T HE N GET THE CONSOLE KEY.

5B7B

3A0300

LIST:

LDA

I0BYTE

5B7E

E640

ANI

01 OOOOOOB ; CHECK ASSIGNMENT

5B80

C27A5C

JNZ

CRT0UT

5B83

3A0AFE

PRINTER:

LDA

URCONT+OAH

5B86

E601

ANI

01

SB88

CA835B

JZ

PRINTER

5B8B

79

MOV

A,C

5B8C

FE5C

CPI

'V ;holb printer?

5B8E

CA625B

JZ

CONIN JC0NIN UILL RELEASE ON ANY KEY

5B91

3202FE

STA

URCDNT+2

5B94

C9

RET

5B95

3E 1 A

READER:

MVI

A, 1 AH ;F ORCE EOF FOR DUMMY READER

5B97

C9

RET

SECTION NOT SH0UN

PRHSG:

JPRINT

MESSAGE AT II, L TILL 0

5C1 8

7E

MOV

A,M

5C1 9

B7

ORA

A

; ZERO 7

5C1 A

C8

RZ

GCIB

EZ

PUSH

H

JMORE TO PRINT

5C1C

4F

MOV

C , A

5C1B

CD725C

CALL

C0N0UT

5C20

El

POP

H

5C21

23

1NX

H

5C22

C3185C

JrtP

1-RrlSG

VIDEO

HARD COPY

ROUTINE

URITTEN BY GLENN STOK

CCOO

=

3CRN

EQU

0CC00H

; VIDEO SCREEN ADDRESS

5C25

C5

HARDCOPY: PUSH

B

; SAVE REGS

5C26

E5

PUSH

H

5C27

21 00 C C

LX I

H,SCRN

; SCREEN ADDRESS

5C2A

7E

UP 1 :

H0V

A,M

; L 00 K FOR FIRST

5C2B

FE20

CPI

' *

; NON -BLANK LINE.

5C2D

C2345C

JNZ

VP2

5C30

23

I NX

H

5C31

C32A5C

JMP

VP1

5C34

7B

VP 2 :

MOV

A,L

5C35

E6CG

ANI

1 1000000B ; SET TO LINE BEGINNING

5C37

6F

H0V

L, A

5C38

7D

VP3:

MOV

A,L

; PRINT REST OF SCREEN

5C39

E63F

ANI

001 1 1 1 1 1B JCHECK END OF LINE

5C3B

C2545C

JNZ

VP4

5C3E

CD675C

CALL

CRLF

5C4 1

E5

VP5:

PUSH

H

JCHECK FOR REST OF

5C42

7E

VP6:

MOV

A,M

ISCREEN BLANK

5C43

FE20

CPI

5C45

C2535C

JNZ

VP7

5C48

23

1NX

H

5C49

7C

MOV

A,H

5C4A

FED0

CPI

ODOH

;END OF SCREEN?

5C4C

C2425C

JNZ

VP 6

JNQT YET.

5C4F

El

POP

H

; RESTORE HI REGISTERS

5C50

C3625C

JHP

VPS

jRETURN . NO MORE TO PRINT

5C53

El

VP7:

POP

H

JREST0RE NEXT LINE TO PRINT

5C54

4E

VP4:

MOV

C,M

5C55

CD835B

CALL

PRINTER

5C58

23

INX

H

5C59

7C

MOV

A, H

5C5A

FEB0

CPI

ODOH

5C5C

C2385C

JNZ

VP3

5C5F

CD675C

CALL

CRLF

5C62

El

VP8:

POP

H

JRESTORE REGS

5C63

Cl

POP

B

5C64

C3625B

JMP

CONIN

;N0U GO GET CHARACTER.

5C67

0E0B

CRLF

MVI

C,0DH

;cr

5C69

CD835B

CALL

PRINTER

5C6C

0E0A

MVI

C,0AH

;lf

5C6E

CD835B

CALL

PRINTER

5C71

C9

RET

VIDEO CONTROL FOR CRT

- ROUTINE FOR CP/M BIOS MODULE

URITTEN BY

GLENN STOK

, STOK COMPUTER INTERFACE

004E

=

C

:urs

EQU

4EH

;REL. CURSOR L0C. STORAGE

00D0

=

SEND

EQU

ODOH

; E ND OF SCREEN PAGE.

0040

=

LINE

EQU

64

;LINE LENGTH

0020

=

BLANK

EQU

20H

; 6 LANK

5C72

3A0300

C0N0UT:

LDA

I0BYTE

5C75

E601

ANI

00000001 B JCHECK 1/0 ASSIGNMENT

5C77

CA835B

JZ

PRINTER

Program continues.

is my CBIOS. Study the CONIN
routine, which reads the key-
board and checks for function
keys. Note that I wrote the rou-
tine to look for a tilde (~) key.
This is hex 7E. You can choose
another, but make sure you will
never need it for anything else.
This key becomes a “function
key.” Maybe your keyboard has
function keys that you can use.

Implementation

Now look at the HARDCOPY
routine in my CBIOS. Note the
EQU for the screen address of
my memory-mapped VDM. Re-
place this with the proper ad-
dress for your system.

Most memory-mapped video
has 16 lines and 64 characters
per line. This is because this
size conveniently uses a IK
block of memory (16 times 64 is
1024, or IK). If your video is not
16 by 64, then this will consider-
ably change the logic I have
used in the routine. But maybe
you would like to play with it.

Anyway, if you have a 16 by 64
display, let’s continue. Insert
the code of Listing 1 or 2 into
your CBIOS and put the FUNC-
TION KEY check in your present
“keyboard read” routine. Jump
to the HARDCOPY routine if the
key matches. Correct the call to
the PRINTER routine in Listing 1
or 2. You should call your PRINT-
ER routine in your CBIOS.

The HARDCOPY routine
saves and restores all affected
registers so as not to interfere
with any running programs. It
will start its transfer to the print
device at the beginning of the
first non-blank line. It will print
up to and including the last non-
blank line.

To do this I have it check if the
rest of the screen is blank each
time it starts a new line. Even
though this is redundant, it does
not slow down the printer be-
cause the printer, being
mechanical, is even slower. The
alternative is to search, once
and for all, before the start and
save the ending address to com-
pare with. I decided against this
so as not to create an extra
burden for anyone who wants to
put the routine in a PROM chip.

The ASCII codes recognized
by video boards sometimes dif-
fer from the codes recognized

170 Microcomputing, October 1980

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i/* Reader Service index— page 241

Microcomputing , October 1980 171

Listing 3 continued.

5C7A

2A4E00

CRTOUT :

LHLB

CURS

5C7D

EB

XCHG

{PUT RELATIVE CURSOR IN D

5C7E

2100CC

LXI

H.SCRN

;PUT SCREEN ADDRESS IN HL

SC81

19

DAD

I'

;get absolute cursor loc.

5C82

41

HOV

B,C

5C83

7E

MOV

A,M

5C84

E67F

ANI

7FH

; TURN OFF CURSOR

5C86

77

MOV

H, A

5C87

78

MOV

M

;CHECK FOR CONTROL CHARS.

5C88

FEOC

CPI

OCH

{ERASE SCREEN

5C8A

CAAA5C

JZ

CLRCRT

SC8D

FE07

CPI

07

5C8F

CAA43C

JZ

RINGBELL

5C92

FE08

CPI

08

; CTL H (BACK SPACE)

5C94

CABC5C

JZ

B3

5C97

FEOA

CPI

OAH

JUNE FEED

5C99

CAC15C

JZ

LF

5C9C

FEOD

CPI

ODH

{CARRIAGE RETURN

5C9E

CAF35C

JZ

CR

5CA1

C3FB5C

JhP

OTHER

{PUT OUT ANY OTHER CHAR. AS IS.

SCA4

0E07

RINGBELL: MVI

C,Q7

5CA6

CB835B

CALL

PRINTER

5CA9

C9

RET

5CAA

2100CC

CLRCRT

LXI

H,SCRN

{CLEAR THF SCREEN

5CAD

3620

CLR

MVI

M, BLANK

{BLANK OUT THIS LOCATION.

SCAF

23

INX

H

5CB0

7C

MOV

A,H

5CB1

FEDO

CPI

SEND

{END OF SCREEN 7

5CB3

C2AD5C

JNZ

CLR

5CB6

210000

LXI

H,0

{HOME THE CURSOR.

5CB9

C3015B

JHP

PUT

5CBC

IB

BS

DCX

D

5CBD

EB

XCHG

5CBE

C3015D

JMP

PUT

5CC1

214000

LF

LXI

H,LINE ;

{LINE FEED

5CC4

19

DAD

D

{ADD LINE LENGTH TO REL. CURSOR

5CC5

CDCB5C

CALL

SCROLL ;

{DO SCROLL IF END OF SCREEN

5CC8

C3015B

JHP

PUT

5CCB

7C

SCROLL

HOV

A,H

5CCC

FE04

CPI

4 ;

{CHECK IF PAST THE SCREEN AREA.

5CCE

B8

RC

{DO NOTHING IF NOT

5CCF

E5

PUSH

H

by printers. Most printers re-
spond to true ASCII codes, but
some video boards have graph-
ics abilities. To tell printable
characters from graphics, these
boards may use the high-order
bit (usually for parity) to trigger
the graphics representation of a
byte. To print a printable charac-
ter, this bit may have to turn on
or off. You could add an 01 or

ANI to OR or AND, respectively,
each byte before calling your
PRINTER routine.

Check if this is necessary in
your case. VDM does not require
this, but the Polymorphic video
display may have to have the
parity bit shut off (ANI 7FH) for
some printers to recognize the
byte as the proper character. As
for graphics, you’ll have to sub-

5CD0 1100CC

LXI

D,SCRN {START SCROLL FROH THE TOP

5CD3 2140CC

LXI

H,SCRN+LINE {SET HL TO SECOND LINE

5CD6 7E

SUAP

MOV

A,H {GET CHAR.

5CD7 23

INX

H

5CD8 EB

XCHG

{GET ADDRESS OF LINE ABOVE.

5CD9 77

HOV

H, A {PUT THE CHAR. THERE

5CDA 23

INX

H

5CDB EB

XCHG

5CDC 7C

MOV

A,H

5CDD FEDO

CPI

SEND {IS SCREEN FINISHED?

5CDF C2D65C

JNZ

SUAP

5CE2 EB

XCHG

5CE3 0620

HVI

B, BLANK {BLANK THE LAST LINE

5CE5 70

LAST

HOV

H,B

5CE6 23

INX

H

5CE7 7D

HOV

A, L

5CE8 FEOO

CPI

0

5CEA C2E55C

JNZ

LAST

5CED El

POP

H {GET BACK REL. CURSOR

5 CEE 11C0FF

LXI

D.O-LINE

5CF1 19

DAD

D {HOVE UP ONE LINE.

5CF2 C9

RET

5CF3 3EC0

t

CR

HVI

A, 1 1 000000B {GO TO BEGINNING OF LINE.

5CF5 A3

ANA

E

5CF6 5F

HOV

E, A

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COOSOL, INC. po BOX 743, ANAHEIM, CA 92805 (714) 545-2216 7 Days a Week

172 Microcomputing, October 1980

stitute nonprintable characters
with a printable one. My VDM
doesn’t have graphics, so I had
no need for this routine. Also
note that if a blank is not repre-
sented by a hex 20 with your vid-
eo board, then you’ll have to cor-
rect the CPI ’ ’ instructions in
listings 2 and 3.

I’ll be glad to help with any
questions, if you help me by in-
cluding a stamped, addressed
envelope.

Enjoy the new power you now
have at the touch of a key. But
be sure that there’s paper in that
printer! ■

5CF7

EB

XCHG

5CF8

C3015D

JHP

PUT

5CFB

70

OTHER

MOV

H,B

JDISPL AY CHAR.

5CFC

13

INX

D

; I N C R . CURSOR

5CFD

EB

XCHG

5CFE

CDCB5C

CALL

SCROLL

JSCR0LL IF NECESSARY

5 D0 1

7 C

PUT

MOV

A, H

; PUT CURSOR IN NEU LOCATION ON

SCREEN

5 DO 2

E603

ANI

3

;MAKE RELATIVE AGAIN

5 DO 4

67

MOV

H, A

5 DOS

224E00

SHLD

CURS

JUPDATE CURSOR

5 DO 8

1100CC

LXI

D, SCRN

5 DOB

1?

DAD

D

5D0C

7 E

MOV

A,M

;GET CHAR. UNDER CURSOR

5 DO Ii

F680

ORI

80H

;SET CURSOR ON

5D0F

77

MOV

M, A

5D10

C9

RET

5D11

ODOAOAQA

SIGN0N :

DB

0DH,0AH,

,0AH,0AH

5D15

2020202020

DB

ST0K CP/M SYSTEM - VERSION

5/10/79'

5D42

ODOAOO

DB

0 D H , 0 A H ,

,0

5D45

END

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Reader Service index— page 241

Microcomputing, October 1980 173

Bridging the 1 pF
To 100,000 uF Gap

Take the guesswork out of capacitor values
with this inexpensive digital capacitance meter.

Robert J. Stetson
Applications Engineer
BASF Systems
Crosby Dr.

Bedford, MA 01730

D efective capacitors can
smoke expensive compo-
nents in your projects and
cause all kinds of general grief.
Nothing makes our systems act
more demon possessed than a
problem capacitor deep in the
bowels of an otherwise perfect
machine. Before you call in the
exorcist, build this digital ca-
pacitance meter and start veri-
fying capacitors before they go
into the system. Later, if they
fail, you will have the means to
root them out.

The digital capacitance meter
is not only capable of verifying
the quality of a known value of
capacitor, but also can unmask
that unmarked capacitor we’ve
all been known to wonder about
from time to time.

The limits of this unit span
from 1 pF through 100,000 uF.
Needless to say, it accommo-
dates all of my needs. The cost
is low, too, right around $35.
Considering all the unit can ac-
complish in the way of testing a
long range of capacitance val-
ues, it’s quite easy to use.

In the short time I’ve had my
unit, all the capacitors in my
parts cabinet have been test-
ed, and the defective ones

E3 = x times 10 3
E2 = x times 10 2
El = x times 10
E0 = x times 0
E-1 = x times 10" 1
E-2 = x times 10* 2
E-3 = x times 10' 3
E-4 = x times 10* 4
E-5 = x times 10' 5
E-6 = x times 10' 6

(The value given here is correct as shown in the readout.)
(The value given here is correct as shown in the readout.)
(The value given here is correct as shown in the readout.)

Table 1.

Fig. 1. Control panel layout.

have been weeded out. Next, I
plan to take advantage of some
gigantic unmarked capacitor
bonanzas.

Operating the Digital
Capacitance Meter

The control panel layout Is
shown in Fig. 1. The toggle
switch in the lower left-hand
corner of the control panel se-
lects between the high- and
low-order group of ranges. With
the group-select switch in the
EH position, the range-control
switch selects the group of
ranges E-1 through E3. The
switch in the EL position
causes the range selector to
operate from E-6 through E-2.

The ranges identified by the
symbols E-6 through E3 are ab-
breviated expressions in scien-
tific notation. The converted ex-
pressions are listed in Table 1.
The decimal point is adjusted
as directed by the expression,
unless otherwise directed in
parentheses.

The range EO is correct as
shown in the readout because
it is given as the direct value of

the capacitor in microfarads.
This range covers the value of 1
uF through 99 uF. In the range
E-1, the value is correct as
shown in the readout because
the internal logic places the
decimal point for us, so that the
readout reads “X.X”. This
range, then, covers the values
0.1 through 9.9 microfarads.

In the E-2 range, the decimal
is also placed, so that the read-
out shows “.XX” uF. This is the
range .01 uF through .99 uF. All
of the other ranges require you
to place the decimal according
to the value of the exponent.
The resulting value will always
be in microfarads. For instance,
1 pF is equal to .000001 uF.

The power switch is optional
and may be omitted if the unit is
not going to be left plugged in
when not in use. Upon applica-
tion of power, the unit has a
built-in power on reset. The unit
should power on with the ready
lamp illuminated and 00 in the
readout.

The illuminated ready lamp
indicates that the unit is ready
to test a capacitor. Select the

Fig. 2. Circuit operation.

174 Microcomputing, October 1980

Fig. 3. Range control.

♦5V

7400

best range for the capacitor to
be tested and connect the
black clip to the negative lead
(if it is an electrolytic) and the
red clip to the positive lead.
Press the test push button and
the ready lamp goes out. As-
suming that the capacitor is
good and that the correct range
was selected, a number ap-
pears in the readout. This,
along with the exponential
shift, is the value in uF.

If you select the correct
range, but the value in the read-
out is much higher than that
shown on the cap, it’s leaky.
Also, a leaky cap may cause the
display to go into an overrange
condition, causing the readout
to flash on and off. If the cap is
shorted, the readout will flash
on and off and the counter will
continue to count.

Theory of Operation

An overall view of the circuit
operation is shown in Fig. 2.

The unit has two groups of
ranges, each with its own clock.
Each group, in turn, has five
ranges.

In Fig. 3, the capacitor to be
tested is connected with the
positive end on the red clip and
the negative end on the black
clip. If the value of the capaci-
tor is, say, .01 uF, the group-
select switch should be set on
EL (Exponential Low range),
and the range-select switch
should be set to E-2. This set-
ting on the group-select switch
will cause the far left decimal to
light, and the readout will show
.00 when the unit is powered up.

In this situation, the group-
select switch (top section) pulls
E-2* to ground, and the range-
select switch (top section) pulls
E-2 to ground. The combination
of E-2 and E-2* in Fig. 4 causes
dp2 to go low. The signal dp2
goes to Fig. 5, where the deci-
mal point is lit.

The group-select switch also

pulls DB10 to ground in the EL
position. DB10 goes to Fig. 6,
where it presets the 7474 latch.
With the latch preset, the Q out-
put goes low and enables the
7402 NAND gate (C4) to pass
the composite signal generat-
ed by combining TR and TX. As
long as DB10 remains low, the
number of pulses gated through
the NAND gate will equal the
number of pulses gated out of
CNT. DB10 will remain low as
long as the group-select switch
is in the EL position.

In Fig. 3, the range-select
switch completes a circuit from
R6, through the group-select
switch to the positive end of the
capacitor, to RC, which goes to
Fig. 7, where it becomes the
timing network to pin 6 and 7 of
the 555 timer. The A1 timer (555)
is an astable timer, i.e., it fires
only once each time it is trig-
gered.

The power-on-reset circuit

consists of a 220 uF capacitor
from the clear input to the 7474s
in Fig. 7 to ground. If the power-
on-reset feature is not desired,
the 220 uF cap may be elimi-
nated, but the Ik Ohm resistor
to + 5 volts will still be required
as a pull-up. The duration of the
reset pulse to the clear input on
power up is determined by the
RC time constant of the pull-up
resistor and the reset capacitor
combination. For 220 uF times
Ik Ohms, this is .22 seconds.

When the unit powers up, the
clear input to the 7474s goes
high .22 seconds later than the
preset input to ensure the pow-
er-up state of the unit. The first
latch illuminates the ready
lamp on the front panel, while
the second latch resets GO and
SEQ.

In Fig. 7, SEQ goes high and
primes the trigger network to
the 555 timer. In the low state,
GO holds the other 555 timer re-

Microcomputing, October 1980 175

set on pin 4 of Cl. In Fig. 4, the
555 timer (E5) is also held reset
with GO being low on pin 4. In
Fig. 6, SEQ being high ensures
that the divider (or prescaler) is
being held at a binary 0000. In
Fig. 5, SEQ holds the display
counter at decimal 00, as well
as holding the 7474 overrun de-

tector in a reset condition.

The unit is now ready to pro-
vide an accurate test, and the
two reference clocks are halt-
ed. The low-range reference
clock is in Fig. 4 (E5), with the
clear held low by GO. The clocks
both have inverter-drivers at the
outputs to flip the signal from

220 a

(7)

» dp2

41

Bin

A

r 9

B

a in

C

"0

B4

D

7490

Fig. 5. Counter and output display.

pin 3 of the 555s, so that the
signal is normally low with posi-
tive-going spikes. Also, the use
of transistor driver stages en-
sures constant loading on the
output of the timers and pre-
vents frequency shifts from oc-
curring due to loading or noise
coupling at the output.

The high-range reference
clock is in Fig. 7 and has the
same identical configuration.
The only differences in the two
clocks are the values placed on
the timing components, which
generate a low-group selected
reference frequency of 28 kHz
and a high-group selected ref-
erence frequency of 1.5 kHz.

To control the exact number
of clock pulses occurring dur-
ing the timing window, the two
clocks are held in a reset state
until you press the test button.
If the reference clock were free
running, theclock pulses would
not be uniformly framed in the
timing window generated by

TX, affecting the unit’s accu-
racy. The unit would be un-
stable, and the reading would
tend to vary from test to test
with the same capacitor.

With the capacitor under test
in place and the ready lamp lit,
press the test push button. The
two 7474s in Fig. 7 preset, and
the ready lamp extinguishes.
GO goes high and SEQ goes
low, firing the 555 (A1) timer,
which generates a single posi-
tive-going pulse whose dura-
tion is under the control of the
capacitor under test and the re-
sistor selected by the group-
select switch and the range-
select switch combination. SEQ
also goes to Fig. 6, where the
clear releases from the 7490
decade counter, and to Fig. 5,
where the 7474 overrun detec-
tor has a high applied to the
clear and D inputs to enable the
detector. Also, SEQ going low
enables the display counter to
display the number of pulses

Ir

C5

7474

C5

7474

o GO

; 220/iF

♦5V

Fig. 6. Prescaler.

Fig. 7. Timing and control.

176 Microcomputing, October 1980

that were gated into CNT.

At the instant that SEQ goes
low, GO goes high to remove
the clear from both the highl-
and low-range reference clocks.
Both the T1 and T2 clocks go to
Fig. 4, where the correct clock
is selected by E-1* or E-2*.
Since the low range is being
selected in Fig. 3, E-1* is high
and E-2* is low. With E-1 * high,
the TR2 (low-range clock) is en-
abled, and TR1 is inhibited by
E-1* being low. TR operates at
28 kHz and is gated through
Fig. 6 under the control of TX.

If the capacitor is .01 uF, the
gating of TR and TX will output
one pulse. If a .05 uF capacitor
is being tested, the pulse on TX
will be five times as long, and
five clock pulses will be gated
through. Since the prescaler is
turned off by DB10, CNT is iden-
tical to the signal on pin 11 of
C4 in Fig. 6.

These pulses are tallied by
the display counter in Fig. 5 and
directly decoded and displayed
on the control panel display.
The number showing on the dis-
play is the value of the capaci-
tor in microfarads. The deci-
mal, when not lit, is placed by
using the exponent indicator
selected by the range-select
switch.

In the event that the maxi-
mum displayed value of 99 is
exceeded, the D output of B4
goes low when the 7490 counts
up past 9 to 0. This places a
positive-going slope on the T in-
put to the 7474 overrange de-

tector.

The output of the 7474
switches high and enables CLK
to be gated through to alter-
nately switch FLASH high and
low. FLASH goes to pin 4 of the
7447 binary-to-decimal decod-
ers and alternately enables and
disables the outputs a through
g. These outputs are normally
high and are prevented from go-
ing low while pin 4 is low, so the
display flashes on and off. Any
time the display flashes, the
value being displayed is a ran-
dom number and not the value
of the capacitor under test.

The source of the signal CLK
is in Fig. 8, where a 74123 dual
timer free-runs at all times while
power is present, driving CLK
on and off for equal 1/2 second
intervals. The speed of CLK
controls the rate of the flash
when an overrange condition is
detected.

The power supply in Fig. 8 is
simple and direct. The LM 309K
is bolted directly to the cabinet
from the outside with the leads
protruding into the cabinet
through two holes. The regula-
tor doesn’t even get warm. The
transformer is a standard 12
volt filament transformer capa-
ble of delivering 500 to 1200 mil-
liamps. A generous amount of
bypass capacitors used on the
TTL circuits provide complete
stability. Every chip is individu-
ally bypassed with a .01 uF disk
capacitor, and several low-pass
8 uF capacitors were strategi-
cally placed on the board.

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iS Reader Service index— page 241

Fig. 10. PC board layout.

Fig. 9. Full range linearity map.

To test a capacitor of 6.4 uF,
the group-select switch is
placed in the EH position, and
the range-select switch is set to
the E-1 position. This places a
low on the E-1* line, and DB10
goes high along with E-2*. E-1
and E-1 * at the top of Fig. 4 pull
dpi low to Fig. 5 to light the
decimal point dpi. The readout
now shows 0.0 after the reset
button has been pushed.

When the test button is
pushed, the sequence of events
is similar to the low-range test.
There are a couple of differ-
ences. First, with E-1 * low, TR2
is inhibited and E-2* high en-
ables TR1, so that TR operates
at 1.5 kHz. DB10 being high to
Fig. 6, the 7474 is held in a
cleared condition with Q set
low and Q set high. The output
from C4 pin 11 in Fig. 6 is gated
to the 7490 divide-by-10 pre-
scaler. TR and TX gate 640
pulses through to pin 11 of C4.
The 7490 decade counter di-
vides the 640 pulses down to 64
pulses on CNT.

|n Fig. 5, the display counter
counts up to 64 and stops. With
the decimal point dpi lit, the re-
sultant display is 6.4, which is
the value of the capacitor in mi-
crofarads.

Since the full range linearity
of the 555 timer isn’t perfect,
linearity problems arise at the
upper and lower extremes and
the unit becomes pearly impos-
sible to stabilize. For this rea-
son, two clocks were used. A
very fast clock (28 kHz) with no
prescaler is close to linear all

the way down to the tens of pF.
Upon nearing the tens of pF,
the unit becomes increasingly
inaccurate, but still serves as a
good go, no-go tester. An accu-
racy tracking chart is shown in
Fig. 9 for all ten ranges in the
capacitance spectrum.

Due to the long time delays
generated by electrolytic ca-
pacitors, a prescaler is used in
conjunction with a relatively
slow clock. The 1.5 kHz clock
aided in stabilizing the erratic
upper end of the capacitance
spectrum. The accuracy of the
unit tracks better than the ca-
pacitor under test. The capaci-
tor to be tested usually has a
tolerance of 10 to 20 percent.
For a 19,000 uF cap, that’s a
range of 15,000 through 23,000

Fig. 11. PC board layout.

uF.

Five 19,000 uF caps were
sample-tested on the E3 range,
and they all tested at 20,000 to
21,000 uF. At values in excess
of 50,000 uF, the tolerance of
the unit begins to increase, un-
til, at 100,000 uF, the unit’s ac-
curacy is 15 percent. A sam-
pling of 100,000 uF capacitors
measured 85,000 uF, which is
15 percent below their rated val-
ue. The capacitors themselves
were rated at 20 percent toler-
ance, indicating that the unit is
well within reasonable limits
for a capacitor of this value.

Tracking over a majority of
the midrange of the unit is vari-
able, from 1 percent to 5 per-
cent accurate. This was deter-
mined by using ten capacitors
of several values and tracking
the average reading. The toler-
ance of the capacitors was 20
percent, but the average of a
group of ten tracked close to 1
percent. This forms the founda-
tion for my tracking chart and is
the method used to determine
these percentages.

Construction

The PC board layout is shown
in Figs. 10 and 11. The cabinet
was purchased at Radio Shack,
along with the common anode
seven-segment displays. The
wiring was all point-to-point
wire wrap, using 30 gauge. No
unusual parts were used in the
digital capacitance meter. In
fact, I selected them specifical-
ly for their availability and low
cost.

The component values are
not critical, and transistor types
are unimportant. Simply ensure
that they are NPN switching

178 Microcomputing, October 1980

transistors with sufficient gain
to allow reasonable rise and
fall time. Try to get as close as
possible to the clock frequen-
cies and observe timing-related
component values closely. Your
particular wiring scheme may
cause the calibration to be hard
to achieve. If the limit of a
calibrated range is reached, add
or subtract resistance as re-
quired to center the calibration
and reestablish stability. This is
most likely to vary at the upper
and lower extremes of the unit’s
range (especially toward the E-6
and E3 ranges).

When trimming up each
range, favor the end of the
range closest to the EO range
for accuracy. Don’t allow any
single capacitor to set the stan-
dard for a range. About ten ca-
pacitors give a good indication
of how well the range is track-
ing.

The far left decimal point
should light when the E-2 range
is selected (make sure the
group-select switch is on EL),
and the center decimal should
be lit when the selector switch

is on E-1 (make sure the group-
selector switch is on EH). All
other ranges should not have
any decimal point illuminated.
These decimals are set using
scientific notation, as derived
from the range identifier.

Testing Capacitors
of Unknown Value

The truest value of any un-
known capacitor is in the range
closest to EO, where a reading
is obtained. If the readout
shows a value of 00 after the
test button has been pushed,
the range is too high. Switch to
a lower range and try again. If
the display flashes on and off
with a value indicated, the
range is too low. Switch to a
higher range and try again. If
the display flashes on and off
and the display is counting con-
tinuously, either you are much
too low on the range selected
or the capacitor is shorted.

Experience will be your best
teacher in using the digital ca-
pacitance meter. I have come to
trust and rely on mine, which
has never failed me yet.H

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92703. Personal or company checks require two weeks to clear. Terminals in stock are
shipped the business day after receipt of certified funds. All equipment includes factory
warranty.

SHIPPING: We ship freight collect by UPS when possible. Larger terminals are shipped
by motor freight. Air and express delivery is available on all products.

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Reader Service index — page 241

Betting on Old POKEy

Although you can’t always be a winner at the race track,
you can cash in on the animated graphics capability of your PET.

Gary Greenberg
35-63 80th St
Jackson Ht$., NY 11372

O ne of the nice features of the PET is the POKE com-
mand, which places a specific character at a specific
location on the PET’S screen. This permits you to produce
some interesting animated graphics, as illustrated in the
Horse Race program in this article.

Program Operation

POKE puts a given value into a specific location in
memory. Lines 1000-1090 show you the format of the POKE
instruction. The number after the comma is the value placed
into memory. The number before the comma is the address
of the memory location in which the number is placed. As
you can see from the example, either value can be a variable.

The PET screen accommodates 1000 characters in 25
lines of 40 characters each. The data in certain memory ad-
dresses dictate what appears on the screen at any particular
location. The 1000 addresses starting consecutively with
32769 determine the screen display. The numeric value
stored in address 32769 determines what appears in the first
position on the screen (row 1, column 1). The value stored at
32873 determines what appears in the 105th position on the
screen (row 3, column 25).

Every PET character has an assigned number that, when
stored in one of the 1000 addresses, will display the
character at the address indicated. For example, the asterisk
is assigned number 42. When 42 is poked into address 32873
(POKE 32873,42), then the screen will display an asterisk at
row 3, column 25. The asterisk will remain there until you
either poke another value into 32873 or write over that loca-
tion by running your program.

In the Horse Race program, the POKES are used to draw
the horses and advance them across the screen. The number
32, when poked into memory, produces a blank at the in-
dicated screen location. The POKEs are arranged so that
every time a horse is advanced one space, blanks are placed
in all the necessary locations to erase all remnants of the old
horse drawing.

In line 250 I defined the starting positions for each of the
five horses by using the value A(l). As A(l) changes value, the
horses are advanced across the screen. Lines 600-610 deter-
mine which horse will be moved. Subroutine 1000 causes the
horse to be drawn in the proper place on the screen.

This version of Horse Race permits only one player to bet.

Each horse has an equal chance of winning. The computer
will keep track of the player’s winnings. Lines 150-170 are
used to provide for a random starting point for the random
number generator. The PET uses the same sequence of ran-
dom numbers every time you turn it on. Since writing this pro-
gram, I have learned that those lines can be replaced by 150
R = RND(-TI). ■

10 PRINT".!" GGSUB1200
20 PRINTTAB(8> ; "COPVRIGHT 1978 BY"

30 PRINTTAB<9); "GARY GREENBERG"

40 GOSUB1200
50 R 1=500

80 PR I NT "WELCOME TO SILICON VALLEY RACE TRACK. " GOSUB 1200
90 PR I NT "YOU HAVE *508 TO START WITH."

100 PRINT"ALL HORSES ARE 41 0BDST0 WIN. "PRINT
110 PRINT " THE HORSES ARE NUMBERED 1-5."

120 PR I NT "ENTER THE NUMBER OF YOUR HORSE AND"

130 PR I NT "THEN ENTER YOUR BET."

140 GOSUB1200

150 FOR I = 1 TOVAL <RIGHT$<TI$,2)> R=RNB <1 ) : NEXT I
160 T1=INT<1000*RNDC1>>

170 F0RI=1T0T1 R=RND<1 ) ; NEXTI

240 F0RI*1T0VAL<RIGHT$<TI$,2>> R=RND(1 > NEXTI

250 R< 1 >=2 : AC2) = 122 •' A<3>=242 A<J4>=362 • A(5>=482

260 F0RI=1T05 B<I)=0 NEXTI

270 INPUT "HORSE" ;H

280 H=INT<H) : I FH>0ANDH<6THEN3 1 0

290 PR I NT "HORSES ARE NUMBERED 1-5. TRY AGAIN"

300 GOSUB1200 GOTO270
310 INPUT " BET ",BB=ABS<B>

320 I FB<R 1 ORB=R 1 THEN400

330 PRINT" YOU HAVE *";R1; M . ",

350 GOTO310
400 PRINT".!";

410 FORI=1TO10 PRINT IFI22=INT<I22>THENPRINTI22, GOSUB1200

420 NEXTI

430 FGRI=1T05

440 GOSUB 1 000

450 NEXTI

600 R=INT<5*RND<1>+1)

610 <A(R>=A<R>fl

620 I=R GOSUB1000

630 B<R>=B<R>+1

640 IFB<RK34THEN600

650 PR I NT "8" F0RI=1T015 : PRINT NEXTI

660 PR I NT" THE WINNER IS NUMBER", R

670 IFH=RTHENR1=R1+4*B ; GOTO750

680 PR I NT "YOU LOSE. " :R1=R1-B

685 PR I NT "YOU HAVE *";R1, "LEFT. "

687 I FR 1 =0THENPR I NT " YOU ' RE BROKE. COME BACK ANOTHER DAY. " G0T09999
690 INPUT "ANOTHER RACE <Y OR N>",Z*

700 IF LEFT$<Z$,1X>"V"THEN9999
710 GOTO250

750 PRINT" YOU WIN $";4*B
760 PR I NT" YOU NOW HAVE
770 GOTO690
990 GOT09999
1000 P0KE32768+A(I)-1,32
1010 P0KE32768+A< I ) , 39
1 020 P0KE32768+A < I >+l, 176+1
1030 P0KE32768+A< I )+2, 160
1040 P0KE32768+A< I )+3, 95
1050 P0KE32768+A< I >+39,32
1060 P0KE32768+A< I >+40, 73
1 070 P0KE3276S+ A < I > +4 1 , 32
1080 P0KE3276S+A< I ) +42, 32
1090 P0KE3276S+A<I>+43,77
1100 RETURN

1200 F0RJ=1T036 PRINT"-"; NEXT J : PRINT : RETURN
9999 END
READY.

Program listing. Horse Race program in PET BASIC run on a PET printer.
The symbols between the quotes in lines 10 and 650 are the clear and
home symbols, respectively.

180 Microcomputing, October 1980

MICRO MISCELLANY FROM JBE

A to D D to A CONVERTER

6502 MICRO-MICROCOMPUTER

79-287 ASSM.

KIT

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The JBE A-D and D-A Converter can be
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time is 20pS, D-A conversion time is
5pS. Uses include speech, music syn-
thesizing, slow scan TV, and joystick or
paddle control inputs. Uses single
power supply (5V), see JBE 5V power
supply below. Parallel inputs and
outputs include 8 data bits, strobe lines
and latches. Analog inputs and outputs
are medium impedance zero to five volt
range.

APPLE II PARALLEL INTERFACE

80-153 ASSM.

KIT

BARE BOARD

This JBE 3Vax5" Micro-Microcomputer has the following:

• 1024 Bytes of RAM (two 2114s)

• 2048 Bytes of EPROM (2716)

• Uses one 6522 via (documentation inc.)

• 2 8-bit bidirectional I/O ports

• 2 16-bit programmable timer/counters

• Serial Data Port

• Latched output and input with handshaking logic.

• TTL and CMOS compatible
The 6502 Microprocessor is particularly suited for control
functions such as temperature control, burglar alarm,
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faces with the JBE Solid State Switch and A-D and D-A

Converter and uses the JBE 5V power supply (see
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JBE Apple II Parallel I/O Card interfaces
printers, synthesizers, keyboards, and JBE
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KIT $ 59.95

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SOLID STATE SWITCH

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channel version and includes documentation for interfacing with JBE Dimmer Control
(see below). The 1 channel version is also available professionally packaged.

79-282 1 CHANNEL ASSM. $13.95
1 CHANNEL PKGD. $39.95
79-282 4 CHANNEL ASSM. $49.95

KIT $10.95 BARE BOARD $ 6.95
KIT $39.95 BARE BOARD $24.95

POWER SUPPLIES

± 1 2 VOLT POWER SUPPLY

This 2X2V2” power supply uses a wall transformer for
safety and is protected against short circuit and ther-
mal breakdown. It is rated at ± 12 V 120MA and can
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80-161 ASSM. $22.95
KIT $18.95

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5 VOLT POWER SUPPLY

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DIMMER CONTROL

The JBE Dimmer Control has 4 chan-
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APPLE II DISPLAY BOARD

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which makes identification
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CRT CONTROLLER

This intelligent CRT Controller is completely contained on a 6x6%” printed circuit
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8085 CPU
Two 8185s

Two 2716s (1 for software, 1 for user
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Serial Interface RS232 and TTL
Baud rates of 110, 150, 300, 600, 1200,
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Keyboard Scanning System
Uses +5V power supply and ± 12V
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JBE — see above)

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8085 3-CHIP SYSTEM

State-of-the-art system using* 3 IC’s, an 8085, an 8156 and either an 8355 or
8755. The system has the following:

• 3 MHz 8085 CPU • ? serial input/output lines

• 256 bytes static RAM • Instruction set 100%

• 2048 bytes ROM upward compatible with 8080A

• 38 parallel input/output lines 14-bit counter/timer

$ 24.95

8088 5 .CHIP SYSTEM

An 8086 Family microcomputer system using 5 IC’s, an 8088 CPU, and 8284
clock generator, an 8155 RAM/IO/Timer, an 8755A EPROM/IO and an 8185 (IK
x 8) Static RAM. This system has the following:

• 16-bit internal architecture

• Up to 1280 bytes of static RAM

• 2048 bytes of EPROM

• 38 parallel input/output lines

• 14-bit counter/timer ^ O

• Instruction set 100% compatible with the 8086 $Z9iV9

SPARE PARTS

INTEGRATED CIRCUITS
6502 $ 9.95

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CABLE

Standard Dip Jumpers

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CONNECTORS

50 Apple Connector $ 5.95

JOHN BELL ENGINEERING

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!/" Reader Service index— page 241

Microcomputing, October 1980 181

The 16-Bit Time Trials

These assembly-language benchmarks test
a new, improved generation of microprocessors.

Allan Flippin
EECO, Inc.

1601 E. Chestnut Ave.
Santa Ana, CA 92701

S ince my March 1980 article “Assembly-
Language Benchmarks,” several new
microprocessors have become available.
This update will examine four of them: the
8086, 6809, 68000 and Z8000.

I’ve also included three microprocessors

from the first piece: the 370-145 for com-
parison purposes and the LSI-11/23 and
9900 because both have improved execu-
tion speed. I did not recode any of the
benchmarks for these microprocessors, but
simply plugged in the new execution times
from the manufacturers’ information. Ac-
tual listings for the 8086 and 6809 bench-
mark programs are included with the arti-
cle. (Contact the author directly for copies
of other listings.)

The benchmarks and scoring methods

used are the same as for my original article
with the following exceptions:

1. Since my data sample is smaller and
more uniform, I have used averages instead
of medians for my index calculations.

2. Execution times for the multiplication
benchmark are prorated to 16 bits instead
of eight bits.

The Benchmarks

The microprocessor execution times are
based on the clock frequencies listed in

;

8086

TABLE LOOKUP ROUTINE

i

i

37 MICROSECONDS

;

8 INSTRUCTIONS

»

l

17 BYTES

0800

i

START:

ORQ

0800H » SET PROGRAM ORIGIN

0800:

AO

00

09

MOV

AL, CHAR i GET VALUE TO BE SEARCHED FOR

0803:

B9

OA

00

MOV

CX» LENGTH TABLE1 ; GET NUMBER OF TABLE ENTRIES

0806:

BF

01

09

MOV

DI, OFFSET TABLE1 ; GET TABLE BEGINNING ADDRESS

0809:

FC

CLD

; SET UP FOR AUTO- INCREMENT IN 'SCAS'

INSTRUCTION

080A:

F2

AE

REPNZ

&

SC AS

TABLE1 .SEARCH TABLE UNTIL EITHER WE FIND THE CORRECT

i VALUE OR TABLE ENTRY COUNTER GOES TO

0

080C :

75

03

JNZ

ERROR i PROCESS ERROR IF NO MATCH

080E :

8A

45

09

MOV

AL. TABLE2-TABLE1-1 CDI 3 ; OTHERWISE. GET CORRESPONDING

ENTRY

. FROM DATA TABLE

i

-END OF ROUTINE

0812

i

ERROR

EQU

%

0812:

EB

FE

END:

JMP

END i LOOP

-DATA

AREAS

0900

ORG

0900H

0900

CHAR:

DB

? . CONTAINS VALUE TO BE SEARCHED FOR

0901:

00

01

02

03

TABLE1 :

DB

0. 1.2. 3, 4, 5. 6. 7.8.9 i SEARCH TABLE

04

05

06

07

08

09

090B :

00

01

02

03

1

TABLE2:

DB

0, 1. 2. 3. 4, 5. 6. 7. 8. 9 ; CORRESPONDING SEARCH TABLE

04

05

06

07

08

09

Listing 1. 8086 table lookup routine.

182 Microcomputing, October 1980

i

i 8086 BLOCK MOVE SUBROUTINE AND CALLING SEQUENCE

; 694 MICROSECONDS

i 11 INSTRUCTIONS

; 21 BYTES

i CALLING SEQUENCE

0800

START

ORG

0800H

0800

BE

00 09

MOV

SI, OFFSET FROM

0803

BF

00 OA

MOV

DI, OFFSET TO

0806

E8

02 00

i

CALL

MOVE

—END OF

ROUTINE

0809

: EB

FE

END;

JR

END

—BLOCK

MOVE SUBROUTINE

080B

; 8B

DE

MOVE:

MOV

BX, SI

080D:

: FC

CLD

080E

AC

MOVE 1 :

LODS

FROM

080F

AA

STOS

TO

0810

3C

OD

CMP

AL, ODH

0812

75

FA

JNZ

MOVE1

0814;

2B

F3

SUB

SI, BX

0816;

C3

RET

—DATA AREAS

0900

ORG

0900H

0900

FROM

DB

256 DUP (?)

OAOO

TO

DB

256 DUP (?)

SET PROGRAM ORIGIN
LOAD ADDRESS OF SOURCE FIELD
AND ADDRESS OF DESTINATION FIELD
CALL MOVE SUBROUTINE

; LOOP

.SAVE STARTING ADDRESS OF SOURCE FIELD
.SET UP FOR AUTO- INCREMENT

; GET A BYTE FROM SOURCE FIELD
i STORE IN DESTINATION FIELD

; CHECK TO SEE IF CARRIAGE RETURN JUST MOVED
i LOOP BACK IF NOT

; CALCULATE NUMBER OF BYTES MOVED
i EX IT SUBROUTINE

; SOURCE FIELD
; DESTINATION FIELD

Listing 2. 8086 block move subroutine and calling sequence.

Table 1.

I have added charts to compare the mem-
bers of a given manufacturer’s micropro-
cessor family with each other. I assigned
performance indices of “1 .000” to the eldest
family member for all benchmarks and all
categories. Indices for the other family
members are then calculated relative to the
eldest family member. These charts should
indicate the better performance offered by
the newer microprocessors.

The 8086 is the overall winner, doing well
in all categories. It excels in memory utiliza-
tion. This is because its architecture ac-
commodates one- and three-byte instruc-
tions. In many cases, one of these can do
the same task as a corresponding two- or
four-byte instruction on another 16-bit mi-
croprocessor. The result is compact code,
requiring about 20 percent less memory
space than either the 68000 or Z8000.

The 8086 also is fast, although it is slower
than the 68000, which runs at the same
clock frequency. Special-purpose string
processing instructions make the table
lookup the 8086’s fastest benchmark. The
16-bit multiply is its slowest benchmark. It
requires 70 percent more time than the
68000.

In the ease of programming category, the
8086 is on par with the other micropro-
cessors, but these figures don’t mean much
since the variations between the micro-
processors are so small. I feel that the
8086 is more difficult to program than the

68000, LSI-11/23 or 9900. One reason is
that its registers, though more versatile
than the 8080’s, are not completely general-
purpose. Many of the instructions pertain to
specific registers and cannot be used with
other registers. Also, special-purpose in-
structions such as those used for string
processing increase the number of rules
that a programmer must remember in order
to produce working code.

The 68000, though number two in the
overall ratings, is number one in execution
speed. Even though the 68000 and 8086
have the same clock frequency and similar
memory timing, instructions tend to exe-
cute quicker on the 68000. For example, an
instruction to load a 16-bit value from mem-
ory into a data register takes 1.5 microsec-
onds on the 68000. A similar instruction will
take 1.875 microseconds executed on the
8086.

In my opinion the 68000 is one of the
easiest to program. Instead of using spe-
cial-purpose instructions for string manipu-
lation, the 68000 handles these tasks effi-
ciently with Move and Compare instruc-
tions, using the Post-Increment and Pre-
Decrement addressing modes.

The 68000’s memory utilization is only
mediocre. This is the price for having a large
number of registers and addressing modes.
With memory prices dropping rapidly, per-
haps memory utilization is no longer an im-
portant criterion for microprocessor selec-
tion. Curiously, the 6809 performs signifl-

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i/ 0 Reader Service index-page 241

Microcomputing, October 1980 183

\

8086 JUMP TABLE ROUTINE

\

6 MICROSECONDS

3 INSTRUCTIONS

;

10 BYT C4 >

0800

!

START

0R0 0800H

■> SET PROGRAM ORIGIN

0800:

8B 36 00 09

MOV SI, STATE

i LOAD STATE UORD

0804:

D1 E6

SHL SI, 1

; MULTIPLY BY 2

0806:

FF A4 02 09

i

JMP JMPTBL, CSID

, GET JUMP TABLE ENTRY AND JUMP UHERE IT POINTS

i

i

-END OF ROUTINE

080A :

EB FE

END:

i

JMP END

; LOOP

1 —

-DATA AREAS

0900

ORG 0900H

0900

STATE

DU ?

; STATE UORD

0902:

0A08 0A08

i

JMPTBL

DU END, END, END, END, END, END i JUMP TABLE

0A08 0A08

0A08 0A06

Listing 3. 8086 jump table routine.

;

8086 MULTIPLY ROUTINE

;

19 MICROSECONDS

}

2 INSTRUCTIONS

i

}

7 BYTES

0800

i

START

ORG 0800H

i SET PROGRAM ORIGIN

0800:

A1

00 09

MOV AX, NUM1

t GET MULTIPLICAND

0803:

F7

26 02 09

MUL AX, NUM2

i MULTIPLY BY MULTIPLIER AND LEAVE RESULT IN

i

i REGISTERS AX AND DX

i

—END OF ROUTINE

0807:

EB

FE

$

END:

JMP END

i LOOP

i

!

—DATA AREAS

0900

l

ORG 0900H

0900

NUM1

DU ?

i MULTIPLICAND

0902

NUM2

DU ?

i MULTIPLIER

Listing 4. 8086 multiply routine.

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184 Microcomputing, October 1980

iS 192

cantly better than the 68000 in this cate-
gory.

The Z8000 slips behind both the 8086 and
68000 in execution time. The main reason
for this is the Z8000’s slow clock speed and

memory timing. Memory cycles require 750
ns, compared to 500 ns for the 6809, 68000
and 8086.

The Z8000’s best category is ease of pro-
gramming. It requires fewer instructions to

program my benchmarks than the other mi-
croprocessors. However, because of the
“special case” nature of the Z8000’s in-
struction set, it (like the Z-80) is actually
much more difficult to program than the f ig-

*

*

6809

TABLE LOOKUP ROUTINE

#

84 MICROSECONDS

*

8 INSTRUCTIONS

*

*

21 BYTES

4000

*

START

ORG

$4000

SET PROGRAM ORIGIN

4000: B6

50

00

LDA

BYTE

GET BYTE TO BE SEARCHED FOR

4003: B7

50

OB

STA

TABEND

SAVE IN DUMMY TABLE ENTRY

4006: 8E

50

01

LDX

#TABLE1

GET SEARCH TABLE ADDRESS

4009: A1

80

SEARCH

CMPA

, X+

CHECK FOR MATCH AND INCREMENT TABLE POINTER

400B : 26

FC

BNE

SEARCH

LOOP BACK IF NOT

400D: 8C

50

OB

CMPX

#TABEND

CHECK FOR MATCH ON DUMMY ENTRY

4010: 22

03

BHI

ERROR

GO PROCESS ERROR IF SO

4012: A6

88

OA

«

LDA

OFFSET- 1, X

OTHERWISE, GET CORRESPONDING ENTRY FROM DATA TABLE

*

*

-END OF ROUTINE

4013

ERROR

EQU

*

4015: 20

FE

END

*

BRA

END

LOOP

*

*

-DATA

AREAS

5000

ORG

$5000

5000: 00

BYTE

FCB

0

CONTAINS VALUE TO SEARCH FOR

5001: 00

01

02

03

TABLE1

FCB

0, 1 1 2. 3, 4, 5, 6, 7,

8,9 SEARCH TABLE

04

05

06

07

08

09

500B : 00

TABEND

FCB

0

DUMMY ENTRY

500C : 00

01

02

03

TABLE2

FCB

0, 1/2, 3, 4, 5, 6, 7,

8,9 CORRESPONDING DATA TABLE

04

05

06

07

08

09

000B

OFFSET

EQU

TABLE2-TABLE1

OFFSET BETWEEN TABLES

Listing 5. 6809 table lookup routine.

*

*

6809

BLOCK MOVE SUBROUTINE AND CALLING SEQUENCE

*

1109

MICROSECONDS

*

11

INSTRUCTIONS

*

*

25

BYTES

*

*

—CALLING SEQUENCE

4000

START

ORG

$4000

SET PROGRAM ORIGIN

4000 8E

42

00

LDX

#FRQM

LOAD ADDRESSES OF SOURCE AND

4003: 10

8E

43

00

LDY

#T0

DESTINATION FIELDS

4007: BD

41

00

*

JSR

MOVE

CALL BLOCK MOVE SUBROUTINE

*

»

—END OF ROUTINE

400A: 20

FE

END

*

BRA

END

LOOP

*

*

—DATA

AREAS

4200

FROM

EQU

$4200

SOURCE FIELD

4300

TO

*

EQU

$4300

DESTINATION FIELD

*

*

-BLOCK MOVE SUBROUTINE

4100

ORG

$4100

SET SUBROUTINE ORIGIN

4100: 34

10

MOVE

PSHS

X

SAVE SOURCE FIELD ADDRESS ON STACK

4102: A6

80

MuVEl

LDA

, X+

GET A BYTE FROM SOURCE FIELD AND INCREMENT POINTER

4104: A7

AO

STA

, Y+

SAVE IN DESTINATION FIELD AND INCREMENT POINTER

4106: 81

OD

CMPA

#$0D

CHECK FOR CARRIAGE RETURN JUST MOVED

4108: 26

F8

BNE

M0VE1

LOOP BACK IF NOT

4 1 OA : IF

10

TFR

X, D

MOVE ENDING SOURCE FIELD ADDRESS TO D REG.

410C : A3

El

SUBD

, S++

SUBTRACT BEGINNING SOURCE FIELD ADDRES FROM IT TO

*

CALCULATE NUMBER OF BYTES MOVED

*

(ALSO, TAKE SOURCE FIELD ADDRESS OFF STACK)

410E: 39

RTS

EXIT SUBROUTINE

Listing 6. 6809 block move subroutine and calling sequence.

Microcomputing, October 1980 185

*

*

6809

JUMP TABLE ROUTINE

*

8 MICROSECONDS

*

4 INSTRUCTIONS

*

*

9 BYTES

4000

*

START

ORG

*4000

SET PROGRAM ORIGIN

4000:

B6

50 00

LDA

STATE

GET STATE BYTE

4003:

48

ASLA

MULTIPLY BY 2

4004:

8E

50 01

LDX

#JMPTBL

LOAD JUMP TABLE ADDRESS

4007:

6E

96

*

JMP

C A> X3

GET JUMP TABLE ENTRY AND JUMP WHERE IT POINTS

*

*

dry L/ ur nuu i irac.

4009:

20

FE

END

*

*

BRA

END

ADC AC

LOOP

nKtnw

5000

ORG

*5000

5000:

00

STATE

FCB

0

STATE BYTE

5001:

4009 4009
4009 4009
4009 4009

JMPTBL

FCW

END. END. END. END.

END, END JUMP TABLE

Listing 7. 6809 jump table routine.

ures indicate.

The 6809 does surprisingly well consider-
ing its 16-bit competition. It consistently
outperforms all of the previously tested
eight-bit microprocessors in all categories.
Its execution time ratings are better than
both the LSI-1 1/23 and the 9900. Its memory
utilization is second only to the 8086. This is

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impressive for what amounts to an up-
graded 6800.

However, I must disclaim the 6809’s good
numerical performance in the multiplica-
tion benchmark. Since the 6809 does not
have a divide instruction, its real perfor-
mance in arithmetic processing will be
much less than indicated by my bench-
mark. Even so, the 6809 should perform bet-
ter in arithmetic processing than the older
eight-bit microprocessors.

Conclusions

All of the microprocessors perform quite
well. The overall rating index for the lowest-
ranked microprocessor is only 50 percent
higher than that for the highest-ranked one.
With such a small variance in performance,
price may therefore become the deciding
factor when choosing between the micro-
processors in this comparison.

The new 16-bit microprocessors offer sig-
nificant improvements in performance over
their eight-bit predecessors. On the aver-
age, the 16-bit microprocessors executed
my benchmarks two to three times as fast
as the earlier eight-bit microprocessors.
Their benchmarks also required about half
as many instructions and 25 percent less
memory space. However, as demonstrated
by the 6809, eight-bit microprocessors can

Microprocessor

Clock Frequency/Cycle Time

8086

8 MHz clock frequency

68000

8 MHz clock frequency

Z8000

4 MHz clock frequency

6809

2 MHz clock frequency

LSI-1 1/23

300 ns micro-cycle

9900

4 MHz clock frequency

Table 1. Clock frequencies.

*

* 6809 MULTIPLY ROUTINE

#

* 21 MICROSECONDS (FOR 16 BITS)

* 3 INSTRUCTIONS

* 7 BYTES

*

4000

START

ORG

*4000

SET PROGRAM ORIGIN

4000:

B6

50

00

LDA

NUM1

GET MULTIPLICAND

4003:

F6

50

01

LDB

NUM2

GET MULTIPLIER

4006:

3D

*

MUL

MULTIPLY THEM

*

cmh

HC DDIITTKJC

Ur nUU 1 1 Pit

4007:

20

FE

END

*

BRA

END

LOOP

*

AREAS

DATA

5000

ORG

*5000

5000

OO

NUM1

FCB

0

MULTIPLICAND

5001:

00

NUM2

FCB

0

MULTIPLIER

Listing 8. 6809 multiply routine.

186 Microcomputing, October 1980

PMC-80

Level II 16K at $645

SOFTWARE COMPATIBLE

• Reads all Level II BASIC tapes

• Reads all SYSTEM tapes

• Full range of peripherals

The PMC-80 is a “work-alike” computer
to the popular TRS-80* Model I, Level II
by Tandy, Radio Shack. The PMC-80 has
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with programs from Radio Shack and
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reads standard Radio Shack programs
for the TRS-80.*

Sold through computer stores.

• Video output for monitor and TV

• Optional FASTLOAD at 8000 band

• Optional Upper/Lower case

The PMC-80 will operate with any of the
many peripherals Radio Shack and
other independent vendors have in-
vented to plug into the TRS-80.* Most
importantly, the Interface Adapter per-
mits Expansion Interfaces with memory
expansion to 48K to be added. An
Expansion Interface will also permit the
addition of Radio Shack compatible
5 '/4 " disks and disk operating systems,
RS 232, printers, etc.

TRS-80 is a registered trademark of Tandv/ Radio Shack.

Personal Micro Computers, Inc.

475 Ellis Street, Mountain View, CA 94043 (415) 962-0220

Reader Service index— page 241

Microcomputing, October 1980 187

be made to perform quite well, and actually
better than some 16-bit microprocessors.

One of the selling features for the 8086,
68000 and Z8000 is the amount of memory
they can access. All three can address mil-

lions of bytes, which should be plenty for
most hobbyists. However, I limited my ad-
dressing range to 65,536 bytes. If more
memory is addressed, the code will be larg-
er and slower. ■

TABLE LOOKUP BLOCK MOVE JUMP TABLE MULTIPLY

PROCESSOR

TIME

RANK

INDEX

TIME

RANK

INDEX

TIME

RANK

INDEX

TIME

RANK

INDEX

8086 :

1

37

1

. 462

1

694

2

. 662

! 6

2

677

19

3

1. 000

1

68000 :

43

2

. 538

488

1

. 466

! 5

1

565

11

2

. 579

Z 8000 :

48

3

. 600

1068

4

1. 019

: 8

3

. 903

20

4

1. 053

6809 i

84

4

1. 050

1109

5

1. 058

: 8

3

903

21

5

1. 105

LSI-U/23 !

94

5

1. 175

1196

6

1. 141

! 10

6 1

129

31

7

1. 632

370-145 !

i

109

6

1. 362

1027

1

3

980

i 8

3

. 903

10

1

. 526

1

9900 !

145

7

1.812 1

1

1 1756

7

1. 675

i 17

7 1

919

21

5

1. 105

I

AVERAGE !

80

!

1

1 1048.

3

i 8.

9

19

Table 2. Execution time (in microseconds).

TABLE LOOKUP BLOCK MOVE JUMP TABLE MULTIPLY

PROCESSOR !

NO.

RANK

. INDEX

NO.

RANK

INDEX

NO.

RANK

INDEX

NO.

RANK

INDEX

8086 :

8

2

i

1.057 S

11

2

1. 013 :

3

1

. 778

!

2

1

933

68000 l

1

8

2

1.057 !

11

2

1. 013 !

4

3

1. 037

2

1

933

1

Z8000 1

5

1

. 660 :

8

1

2

. 737 1

4

3

1 037

2

1

933

6809

8

2

1.057 !

11

2

i.oi3 :

(

4

3

1 037

3

7 1

. 400

LSI-11/23 :

8

2

1. 057 !

11

2

1

1 013 !

|

3

1

778

2

1

. 933

370-145 !

8

2

1. 057 1

13

7

1

1. 197 \

5

7

1. 296

2

1

. 933

9900 1

5

8

2

1. 057 !

11

2

1.013 !

4

3

1. 037

2

1

. 933

AVERAGE }

7. 6

>

1

10 9

3. S

}

2. 1

Table 3. Ease of programming (in number of instructions).

TABLE LOOKUP BLOCK MOVE JUMP TABLE MULTIPLY

PROCESSOR !

NO.

RANK INDEX

NO

RANK INDEX

NO.

RANK

, INDEX

NO.

RANK

i INDEX

8086 ;

17

1

. 708

21

1

. 728 !

10

2

886

! 7

1

. 907

68000 !

26

4

1. 083

28

4

. 970 !

12

4

1. 063

8

3

1. 037

Z8000 !

20

2

833

26

3

. 901 !

12

4

1. 063

8

3

1. 037

6809 !

|

21

3

875

25

2

866 :

9

1

. 797

7

1

. 907

LSI-11/23 :

26

4

1 . 083 !

I 30

5

1. 040 1

10

2

886

8

3

1 037

370-145 I

j

32

7

1. 333

42

7

1. 455 !

14

7

1.241 !

8

3

1. 037

9900 !

t

26

4

1.083 !

1

30

5

1 . 040 !
S

12

4

1 . 063 !

8

3

1. 037

AVERAGE t

24

28. 9

l

11. :

3

!

7 7

; i i

Table 4. Memory utilization (in bytes).

Credits

Thanks to the following people who
helped with this update: Jim Howell, for the
6809 code; Don Barnes of Motorola, for the
6809 and 68000 info; and Paul Stapinski of
AMD, for the 28000 info.

For a further look at the 8086, 68000 and
Z8000 16-bit microprocessors, see Kilo-
baud Microcomputing. “The 16-Bit Super
Processors Are Here,” August 1980, p. 26.

AVERAGES BY BENCHMARK

!

PROCESSOR 1

TABLE

RANK

LOOKUP

INDEX

BLOCK

RANK

MOVE

INDEX

JUMP

RANK

TABLE

INDEX

MULTIPLY
RANK INDEX

8086 1
1

2

. 742 1

1

»

. 801 :

1

. 780 !

3

947

1

68000 :

3

. 893 1

I

2

. 816 :

2

. 888 i

2

. 850

Z8000 1

•

1

1

. 698 1

3

886 :

5

1.001 1

4

1. 008

i

6809 1

4

. 994 1

)

4

. 979 1

3

. 912 1

6

1. 137

LSI-U /23 !

•

5

1

1. 105 1

5

1.065 I

4

. 931 1

7

1. 201

1

370- 14S I

1

6

1.251 1

1

6

1.211 1

6

1. 147 1

1

. 832

9

9900 !

7

•

1.317 1

7

1.243 1

7

1. 340 1

5

1. 025

I

Table 5. Averages by benchmark.

AVERAGES BY CATEGORY

I

1

1

EXECUTION

TIME

EASE OF
PROGRAMMING

MEMORY

UTILIZATION

OVERALL

«

PROCESSOR I

RANK

INDEX

RANK

INDEX

RANK

INDEX

RANK

INDEX

8086 :

2

1

. 700 1

2

. 945 !

1

. 807 !

1

. 817

68000 1
1

1

537 1

4

1.010 1

5

1 . 038 1

2

. 862

i

Z8000 1

3

. 894 i

1

. 842 I

3

. 958 1

3

. 898

6809

5

1.029 1

7

1. 127 1

2

. 861 1

4

1. 006

LSI-1 1/23 1
•

6

1. 269 1

2

. 945 1

4

1. 012 1

5

1. 075

1

370-145 \

9

4

. 943 1

6

1. 121 1

7

1. 266 :

6

1. 110

1

9900 1

1

7

1.628 I

4

1.010 1

6

1. 056 1

7

1. 231

Table 6. Averages by category .

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AVERAGES

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9

PROCESSOR 1

TABLE LOOKUP

BLOCK MOVE

JUMP TABLE

MULTIPLY

1

8085 5

. 938

I

. 947

1

S

. 917 1

. 905

8086 1

l

. 573

1

1

. 754

1

1

. 472 1

1

. 134

1

1

«

AVERAGES

BY

CATEGORY

1

PROCESSOR !

EXECUTION

TIME

EASE OF
PROGRAMMING

MEMORY

UTILIZATION

OVERALL

8085 1

•

. 780

1

1

•

1. 000

1

1

1 . 000 1
1

. 927

8086 i

. 339

1

. 458

1

1

. 654 1

. 484

i i i

Table 7. 8085, 8086 compared to 8080.

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v* Reader Service index— page 241

Microcomputing, October 1980 189

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TABLE LOOKUP

BLOCK MOVE

JUMP TABLE

MULTIPLY

6809

1

. 785 1

. 775

1

. 481 1

. 241

68000 :

1

. 714 1

. 665

1

. 474 1

. 192

AVERAGES

BY

CATEGORY

PROCESSOR !

EXECUTION

EASE OF

MEMORY

OVERALL

TIME

PROGRAMMING

UTILIZATION

6809 1

. 591

1

. 503

1

1

1

. 618 1
«

. 571

68000 1

i

. 303 1

. 486

1

!

1

I

. 745 S

. 511

Table 8. 6809, 68000 compared to 6800.

1

1

1

AVERAGES

BY

BENCHMARK

PROCESSOR !

TABLE LOOKUP

BLOCK MOVE

JUMP TABLE

MULTIPLY

1

Z8000 1

1

1

. 719 1

1

. 933

1

. 607 1

i

. 219

f

AVERAGES

BY

CATEGORY

1

PROCESSOR !

EXECUTION

TIME

EASE OF
PROGRAMMING

MEMORY

UTILIZATION

OVERALL

{

Z8000 !

\

. 532 1

. 445

1

1

1

. 881 1
1

619

Table 9. Z8000 compared to Z-80.

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iS Reader Service index— page 241

Microcomputing, October 1980 191

Machine-Language Techniques

For the 1 802

Puts zip into the COSMAC VIP.

Gerald Strope
1504 Strothmore Court
Raleigh , NC 27609

T he RCA COSMAC VIP is a
single-board processor us-
ing the 1802 chip. The processor
hardware is well explained in
two articles entitled “COSMAC
Double Play” in the May 1979
issue of Kilobaud Microcomput-
ing, so I will not repeat that here.
This article will deal with the use
of machine language in the VIP.

Introduction

The CHIP-8 language that
was developed for the COSMAC
VIP is quite versatile for use in
programming many varied appli-
cations. It is my opinion, though,
that all CHIP-8 programmers will
come to a point where they will
want to do some particular func-
tion that is not possible in
CHIP-8, and will need to write a
machine-language subroutine.

This article is a collection of
ideas and techniques I have
compiled while trying to put ma-

chine language to work in the
VIP. I hope some of these ideas
will be useful to you when you
try your first machine-language
subroutine. I don’t intend to
write a tutorial on the CHIP-8 or
1802 instruction set in this ar-
ticle. CHIP-8 is covered well in
the COSMAC VIP instruction
manual, and I suggest you read
Tom Pittman’s “A Short Course
In Programming” (Netronics,
333 Litchfield Rd., New Milford
CT 06776) for 1802 machine-lan-
guage basics. I will try to explain
my programs in enough detail
so the reader will be able to un-
derstand them, assuming the
reader has some background in
CHIP-8 and 1802 machine
language.

After assembling my COS-
MAC VIP kit and testing it out, I
first wanted to try using some
Elf-2 programs I had seen in vari-
ous magazine articles. I ran into
some differences almost imme-
diately in Elf-2 and VIP hard-
ware. The first problem I ran into
is that the Elf-2 programs use a
6C instruction to input a byte
from the keyboard. The 6C in-
struction is not valid on the VIP;

ADDRESS

CODE

STEP

COMMENTS

0000

F800BB

0

Display-page 0

03

F806B2

R2-06CF, stack pointer

06

F8CFA2

09

F881B1

Rl-8 146/ refresh routine

OC

F846A1

In ROM

OF

90B3

R3-0015, main program

11

F815A3

reg Ister

14

D3

R3»program counter

15

E 269

X-R2, turn on TV

17

3017

branch to 0017 (stop loop)

Listing 1.

ADDRESS

CODE

STEP

COMMENTS

0017

F800B4

1

put 00 Into R4.1,

1A

B5BAAC

R5. 1/ RA , 1, RC.O

ID

F827A4

R4-0027

20

F8C8A5

R5-00C8

23

F8E0AA

RA-00E0

26

D4E5

P-R4, X-R5

28

62

2

m at RX Isd to keyboard latch

29

3637

branch If EF3-1

2 B

25F0

3

R5-1, m at RX-*0

2D

FC0155

add 01/ store In m at R5

30

F0FB10

m at RX-»D/ OR 1mm 10-D

33

324D

branch If D-0

35

3052

go to 0052

37

25F0

4

R5-1/ m at RX-»D

39

8C3A63

RC.0**D/ branch If D not 0

3C

F05A

m at RX-»D/ store In m at RA

3E

3E437B

wait for key released

41

303E

and turn Q on

43

4A2AFE

m at RA-4D/ RA-1/ shift

46

FEFEFE

left four times

49

1C5A

RC+1/ store In m at RA

4B

305A

go to 005A

4D

FC0055

5

reset m at R5 to 00

50

3028

go to 0028

52

0AFBA1

6

m at RA-*D/ OR Imm Al-D

55

3A28

branch If D not 0

57

7B3028

turn on Q/ go to 0028

5A

F820B6

7

load 20 1 nto R6. 1

5D

26

R6-1

5E

963228

R6.0+D, branch If D-0

61

305D

go to 005D

63

2CF0EA

8

RC-1/ m at RX-*D/ X-A

66

FI

M at RA or-D

67

E55A7B

X-5/ store D In m at RA/ Q on

6A

3E5A

branch to 005A when key released

6C

306A

go to 006A

Listing 2.

the VIP uses a keyboard scan
technique instead (see Fig. 1).

Another difference is the use
of the 64 output instruction in
the Elf programs. This output in-
struction will do nothing on the
VIP because it does not have an
output indicator. The TV display
is used for all output.

Inputting and Outputting Data

I will go into methods of solv-
ing both of these problems later
in this article, but first let’s kick
off the display so we can see
what we are doing. The program
in Listing 1 will set up the proper
pointers to use the refresh rou-

tine in the 512 byte ROM. Regis-
ter B.1 contains the desired dis-
play page (page zero, in this
case). Register 2 is the stack
pointer. Register 1 points to the
refresh routine in the ROM.
Register 3 is the main program
register. There is a branch to
itself in position 0017 that we
will remove when we add on to
this program in the next step.

Now page 0 of RAM is dis-
played on the screen. This is
convenient because now we will
enter a program into page 0, and
you can watch a scan loop for
the keyboard increment and see
a shift instruction operate. If

192 Microcomputing, October 1980

1534- FE10

iaxa mi

nan-M-E lnaai

The addition program with an answer without a carry from the high The addition program with an answer with a carry from the high
order position. order position.

you forget a step, as I have done,
you can watch your program
change and disintegrate before
your very own eyes. If you see
this happening, hit the reset
quickly before the refresh point-
ers are wiped out. If that hap-
pens, you have to go back to
0000 and enter it all again.

With the program displayed
on the screen, it is sometimes
easy to see if a register is incre-
menting when you don’t want it
to: Bytes of data will fill up the
screen until they crash into part
of the program, or some other
similar indication.

Listing 2 will scan the key-
board, input a byte of data,
place this byte of data in mem-
ory location 00E0 and check to
see if the byte= hex A1. If it
equals A1, turn on the Q light.

The program works as
follows:

Step 1— Initialize.

Step 2— Load the least signi-
ficant digit (LSD) of memory at
register 5 into the keyboard
latch and test for an EF3 = 1 .

Step 3— Scan 00-10 through
memory at register 5. When it
equals 10, branch to step 5.

Step 4 -Program is at this
step because an EF3 = 1 oc-
curred. Take memory at R5 loca-
tion (this is equal to the key
pressed) and store in memory at
register A. Wait for key released,
then shift data into the left half
of the byte and store back at RA
memory location. Increment
register C, which acts as a flip-
flop indicator to determine if the

left or right half of the byte is be-
ing entered. Branch to de-
bounce routine at step 7. This
wastes time to make sure the
key is fully up before turning the
program loose to start scanning

again.

Step 5— Reset memory at R5
location to 00.

Step 6— Turn on Q if memory
at RA = hex A1 (this step is just
to demonstrate that a full byte

of data can be entered for the
program to examine).

Step 7 — Debounce time
delay. Hex 20 is loaded into
register 6.1. The register is dec-
remented until R6.0 = 00.

4PPRLSS

zm.

STEP

. COMMENTS

0200

630F

1

V3-0F

02

6400

V4-00

04

6600

V6-00

06

6700

V7-00

08

A300

1-300

0A

F00A

2

V0-hex key digit (waits for
any key pressed)

OC

0500

Do machine language routine at 0500

0E

F10A

VI- hex key digit

10

8011

Let V0-V0 logically ORed with VI

12

F055

Store V0 In memory at 1, 1+1

14

7401

V4 + 01

16

3404

Skip if V4-04

18

1 20A

Go to 20A

1A

12 1C

Go to 21C (no-op)

1C

A 3 00

3

1-300

IE

F265

Let V0,V1,V2» memory at I/I+1/I+2

20

650A

4

V5-0A

22

F029

Let l*dlsplay pattern for LSD of V0 (LSDP)

24

D565

Show at V5,V6 coordinate

26

0540

Do machine language routine at 0540

28

6505

V5-05

2A

F029

Let I-V0 (LSDP)

2C

D565

Show at V5,V6

2E

6514

5

V5- 14

30

F129

l-Vl (LSDP)

32

D565

Show at V5,V6

34

054D

Do mach. lang. routine at 054D

36

650F

V5-0F

38

F129

l-Vl (LSDP)

3A

D565

Show at V5,V6

3C

7701

6

V7*01

3E

4701

Skip If V 7 not 01

40

1258

Go to 258

42

4702

Skip If V7 not 02

44

125E

Go to 25E

46

6500

7

V5-00

48

F229

I-V2 (LSDP)

4A

D565

Show at V5,V6

4C

E39E

8

Skip if V3*hex key LSD

4E

124C

Go to 24C

50

E3A1

Skip If V3 not equal hex key LSD

52

1250

Go to 250

54

00E0

e ra se display

56

1200

Go to 200

58

7606

9

V6 + 06

5A

A30 2

1 -302

5C

121E

Go to 21E

5E

7606

10

V6*06

60

0500

Do mach. lang. routine at 0500

62

A3 02

1-302

64

121E

Go to 21E

Listing 3.

Microcomputing, October 1980 193

The screen with Listing 2 running. The circled area shows the hex
character FI, which was entered from the keyboard.

Step 8 — Program is at this
step because an EF3 = 1 oc-
curred. This is the right half of
the byte being entered. Take
memory at R5 and OR it with
memory at RA to make up a full
byte. Also decrement flip-flop
register C.

One additional note on the Q
latch: It is turned off in the re-
fresh routine. This program will
cause the Q audible tone to be

long on the first half of the byte
and short on the second half.
This makes it convenient to be
able to stay in step when enter-
•' ing data.

At this point you might say,
“Now I have entered a byte of
data. If it equals A1, the Q light
will come on with a beep. So
what?” That might be a valid
question, but now we have laid
the groundwork for other ma-

ADDRESS

CODE

STEP

COMMENTS

0500

F806BF

A

RF-06F0

03

F8F0AF

06

OFFE

Memory at RF-*D, shift

08

FEFEFE

left 4 times

0B

5FD4

D+M at RF, return to CHIP-8

0D

F803BC

D

RC-0300

10

F800AC

13

EC

X-C

14

F800F6

00-*D, shift right (clear DF)

17

4CBD

Memory at 300/ operand 1 high
order+RD.l/ RC*1

19

4CAD

Memory at 301/ operand 1 low
order^RD.0/ RC*1

IB

1C

RC* 1 (now-303)

1C

8 D

RD.0+D (operand 1 low order)

ID

F4

Add m at RC *D

IE

AD

D*RD.O (low order answer)

IF

2C

RC- 1 (now-302)

20

9D

RD.l+D (operand 1 high order)

21

74

Add with carry/ m at RC*D/DF

22

BD

D-»RD.l (high order answer)

23

5C

D-*m at RC/ (store high order
answer at 0302)

24

1C8D

RC* 1/ D , 0-*D

26

5C

D-*m at RC, (store low order
answer at 0303

27

1C3B2E

E

RC*1 branch If DF-0 (test
for carry out of high order)

2A

F8015C

M at RC ( 304 )«01

2D

D4

Return to CHIP-8

2E

F8005C

M at RC ( 30 4 ) -00

31

D4

Return to CHIP-8

32

000000

35

000000

00 up to 540

38

000000

40

F806BF

B

RF-06F0

43

F8F0AF

46

0FF6

M at RF-»D/ shift right

48

F6F6F6

four times

4B

5FD4

D-*m at RF, return to CHIP-8

4D

F8F1AF

C

RF-06F1

50

0FF6

M at RF-*D/ shift right

52

F6F6F6

four times

55

5FD4

D-»m at RF/ return to CHIP-8

Li sting 4.

HEX KEYBOARD

62 INSTRUCTION

©©©©

®@©@

© 0 ®©

©©©©

PATA BIT ? *

DATA BIT 2

DATA BIT 1

KEYBOARD

LATCH

Fig. 1. Keyboard operation. A 62
instruction causes the least
significant four bits of the
memory byte pointed to by
register X to be latched in the
keyboard latch. Only the hex key
representing those four bits will
generate an EF3=1 when
pressed. The normal program-
ming technique is to scan each
hex digit into the latch and then
check for an EF3-1 to tell
which key has been pressed.

chine-language programs to
build on.

We now have a subroutine
that could be used with any Elf-2
program, for instance. We are
now able to input variables to a
program when needed. If you
look carefully at position 00E0
on the screen, you will see the
character entered. This is one
way of outputting data, al-
though I must admit it is a bit
crude.

A more sophisticated method
of inputting and outputting data
is to use a combination of
CHIP-8 language with machine-
language subroutines. The

CHIP-8 language combined with
the display patterns stored in
the 512 byte ROM do a nice job
of displaying numbers on the
screen. The programs in List-
ings 3 and 4 (the CHIP-8 and
machine language, respectively)
show the two languages com-
bined. These programs use
CHIP-8 for input and output,
with machine-language shift
and addition subroutines.

The main purpose of these
programs is to demonstrate the
technique of interfacing CHIP-8
to machine language when
there is a desired function that
cannot be programmed in
CHIP-8 alone. It is also useful if
you are new at working the hexa-
decimal.

Try keying in some hex num-
bers and observe how hex addi-
tion works. The addition routine
is an adaption of the routine
published in Kilobaud Micro-
computing, March 1979 (“Pro-
gramming the 1802,” p. 122).
That article was written with the
Elf-2 in mind. These programs
show how Elf-2 programs can be
adapted to the VIP. The program
in Listing 3 works as follows:

Step 1— Initialize variables.

Step 2— Accept four bytes
from the keyboard and store in
memory locations 300,301,302,
303.

Step 3— Load memory bytes
300,301,302 in variables 0,1 and

Variable Allocation

V 0 Most significant data buffer and keyboard entry

V 1 Least significant data buffer and keyboard entry

V 2 Carry position data buffer

V 3 Keyboard character for compare

V 4 Counter for keyboard entry

V 5 X display position (horizontal)

V 6 Y display position (vertical)

V 7 Counter for repeat of display routine

Memory Allocation

0300 Operand 1 high order byte

0301 Operand 1 low order byte

0302 Operand 2 high order byte

0303 Operand 2 low order byte

0304 Carry byte

0302 Answer high order byte

0303 Answer low order byte

Note: The answer is overlayed into memory locations 0302 and
0303 after operand 1 and 2 have been displayed.

Table 1.

194 Microcomputing, October 1980

2 .

Step 4— Set display position.
Display variable 0 twice— first
the least significant digit, then
the most significant digit.

Step 5— Set display position.
Display variable 1 twice— first
the least significant digit, then
the most significant digit.

Step 6— Decision step. First,

SET I TO
OPERAND
2 MEMORY
LOCATION -
SET SCREEN
LOCATION

second or third time at this
point. 1st— Have just displayed
operand 1, branch to step 9.
2nd — Have just displayed
operand 2, branch to step 10.
3rd— Have just displayed an-
swer, go to step 7.

Step 7— Set display position.
Display variable 2 (contains car-
ry indication— 00 or 01).

MACHINE LANGUAGE

INITIALIZE

VARIABLES

ACCEPT 1st
DIGIT FROM
KEYBOARD
PUT IN VO

ACCEPT 2nd
DIGIT FROM
KEYBOARD
PUT IN VI

OR LEFT AND
RIGHT HALF
(VO AND VI)
TOGETHER

LOAD VO. VI
ANO V2 FROM
MEMORY AT
I LOCATION

• STEP 3

1

1

1

1

EQUIPMENT

in

in

SET SCREEN
LOCATION -

1

1

1

1

1

& SOFTWARE

§]Erij

mm

SET SCREEN
LOCATION -
DISPLAY RIGHT
HALF OF VO

SET SCREEN
LOCATION -
DISPLAY RIGHT
HALF OF VI

SET SCREEN
LOCATION -
DISPLAY RIGHT
HALF OF VI

SET I TO
ANSWER
MEMORY
LOCATION -
SET SCREEN
LOCATION

1st. 2nd. OR 3rd,
TIME HERE ? I

i r

! KEY PRESSED !

' - OF 7 i

SET SCREEN
LOCATION -DISP
RIGHT HALF OF
V2 (CARRY)

1

s''

[YES

GET VO MEMORY
LOCATION -
SHIFT TO LEFT
HALF OF BYTE

PUT BACK IN VO

Step 8— Check for keyboard
= 0F. If key = OF, wait until it is
released. Erase screen. Go to
step 1.

Step 9— Set display position
and I to display operand 2.
Branch to second part of step 3.

Step 10— Set display posi-
tion. Branch to add subroutine.
Set I to display answer. Branch
to second part of step 3.

Machine-Language Steps

Step A— Get variable 0 stored
at memory location 06F0. Shift
left four times. Put back in 06F0
location.

Step B— Get variable 0 stored
at memory location 06F0. Shift
right four times. Put back in
06F0 location.

Step C— Get variable 1 stored
in memory location 06F1. Shift
right four times. Put back in
06F1 location.

Step D— Add subroutine. The
program listing is fairly self-ex-
planatory. For a more detailed
explanation see “Programming
the 1802.” This routine is an

adaptation of a routine in that
article.

Step E— Check for carry
(DF = 1). Store 01 for a carry
indication at memory location
0304. Store 00 for a no carry in-
dication.

Conclusion

The program flowchart in Fig.
2 and the memory and variable
usage in Table 1 should allow
you to follow along with the pro-
gram. Some shifting is neces-
sary when working with CHIP-8
variables. The keyboard entry
and display routines in CHIP-8
will only input and output the
least significant half of the byte.
The method I used is to go to the
memory location the variable is
stored in and manipulate it so
the least significant half of the
byte has the correct data in it.
The CHIP-8 program doesn’t
know the difference.

Well, there you have it. I hope
some of these ideas and tech-
niques will be useful for other
COSMAC VIP owners. ■

GET VO MEMORY
LOCATION-SHIFT
LEFT HALF OF
BYTE TO RT 1/2

PUT BACK IN VO

GET VI MEMORY

BYTE TO RT, 1/2

PUT BACK IN VI

ADD OPERANDS
I a 2. STORE
ANS. 8 CARRY
IN MEMORY.

Fig . 2.

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Reader Service index— page 241

Microcomputing, October 1980 195

Poor Man’s Logic Analyzer

Troubleshooting needn’t be a rich man’s sport.

Scott B. Eckert

113 Roxboro Circle , Apt. 6

Syracuse, NY 13211

W hen I had completed
enough of my home-brew
computer system to warrant
power on, I was sadly dis-
appointed. It didn’t work! My
home-brew design is based on
the 6502 microprocessor and
the 6530-004 multipurpose chip.
One of the 6530-004’s purposes
is to provide a IK ROM monitor
program called TIM (Terminal
Interface Monitor). Since it also
provides a serial I/O port, I had
no front panel controls except
for power and reset. Well, I tried
reset and got no response— so I
was in trouble.

Background

Let me explain how TIM com-
municates with the outside
world. When reset is pushed, the
6502 processor wants to go to
locations FFFC/FFFD to get the

two bytes present there. It then
interprets these two bytes as a
sixteen bit address to which to
go and begin executing code as
part of the reset initialization
program for the particular sys-
tem in which it is used.

However, logic on my
6530-004 board detects this
reset and FFFC/FFFD condition
and makes the processor fetch
the bytes from 73FC/73FD in-
stead. These two bytes are in
the end of the ROM (TIM is re-
quired to reside in locations
7000-73FF) and point to the
reset routine that is in the lower
part of the ROM.

This reset program does the
housekeeping chores required
for proper system operation, i.e.,
it initializes the I/O port, ini-
tializes the interrupt vectors,
sets up the stack pointer, etc. In
addition, this routine waits for a
carriage return from the key-
board and determines the baud
rate at which the serial data is
being transmitted.

Anytime you wish to change

baud rates, you simply press re-
set and hit a carriage return. The
routine stores this baud rate
constant for use whenever an
output routine is called. After all
this and more, TIM is nice
enough to print all the register
contents and wait for a com-
mand (when it is working proper-
ly).

The Problem

I knew the processor was do-
ing something in ROM because
the chip-select line on the chip
was being enabled, but I had no
idea what the processor was do-
ing or where it was in ROM.
From the address lines, I could
determine that it was looping
somewhere in the ROM. I had a
listing of the TIM program, but
that didn’t help me at this stage
of the game. It is difficult to de-
cipher sixteen address lines
simultaneously with a single
trace, “trigger-sometimes”
scope. Worse, I had to know if
the correct data was being sent
down the data bus from the
ROM itself.

Well, I wished at that point
that I knew somebody with one
of those fancy logic
analyzers. . . you know, the ones
that cost hundreds to thou-
sands of dollars! I then decided
to build the poor man’s logic
analyzer — something that
would allow me to specify the
address that I want it to, grab
the data off the data bus and
display it to me out in the real

world. As you will see shortly,
this turns out to be a fairly easy
task, really nothing more than a
souped-up parallel I/O port!

The Circuit Details

The DIP switches set the ad-
dress desired to be the trigger
address. Each group of four
switches goes to the input of
one of the 74LS85 4-bit
magnitude comparators. The
address line corresponding to
each switch is also tied to the
proper input on the 74LS85.
When the proper address is on
the address bus (the address
that matches that set into the
DIP switches), the A = B output
of each comparator drives the
cascading A = B input of the fol-
lowing comparator. If all are
enabled, the output from U4-6
will enable the 3 input NAND
gate U6-2.

If the arm switch has been
pressed and flip-flop U5 is set,
the rising edge of the 02 clock
pulse will cause the output of
U6A-12 to go low until one of the
inputs to it goes low again.
Since the address in a 6502
system is valid shortly after 01,
the level on U6-2 is high well be-
fore 02 comes along (see Fig. 1).

When 02 goes high, the neg-
ative-going signal from U6A-12
is inverted again by U6B and
used to enable the 7475 quad-
latches. I he negative-going
edge at pin 12 of U6A also trig-
gers U10, a one-shot multi-
vibrator with approximately a 1

Tods - ADORESS SETUP TIME
Tmds - DATA SETUP TIME
Th - DATA HOLD TIME
Tcyc - CYCLE TIME

Fig. 1. Clock signals and various important times on a 6502 micro-
processor.

196 Microcomputing, October 1980

second pulse width. This drives
an LED to show that the circuit
has been triggered by the occur-
rence of the address set into the
switches.

When 02 returns low again,
pin 12 of U6A goes high. This
positive-going edge toggles flip-
flop U5, if the analyzer is in the
single-shot mode, or does not
toggle it if in the continuous
mode of operation. In the single-
shot mode, the circuit is locked
out from further triggers until
the arm switch is momentarily
moved to the continuous posi-
tion in order to set the flip-flop.
When set to the continuous
mode, it can be used as a stan-
dard latched parallel I/O port
with LEDs, but it can also be
easily moved to any address in
memory.

Some Timing Details

I think a word is in order here
regarding the timing consid-
erations of this circuit to help
adapt this circuit to non-6502
systems. First, the address
becomes valid about 200 nsec
after 01 goes high. The data bus
is floated during this period on a
6502, so there is nothing on the
data bus to grab yet.

Data becomes valid approx-
imately 150-200 nsec after 02
goes high for a write cycle and
must be valid for a minimum of
100 nsec before 02 goes low for
a read cycle. These times are
given for a 1 MHz clock, each
phase being about 500 nsec.
This allows plenty of time for the
data to be at the 7475’s inputs
and meet the data set-up time of
20 nsec. (Data set-up time is
defined as the time required for
the data to be present at the in-
put terminals before trying to
latch it in.)

When the 02 clock goes low,
this is the most critical part of
the whole operation. The data
from a 6502 is valid for approx-
imately 10-30 nsec after the 02
clock phase goes low. With the
two gate delays from the 74LS10
totaling 20-30 nsec, it appears
questionable whether the circuit
will work. However, the typical
delay of a 74LS10 is about 10
nsec, and the typical valid data
time is 30 nsec, so every 74LS10
that I tried worked perfectly.

I suppose this stems partly

from the fact that most devices
are rated conservatively, and, of
course, assuming you don’t buy
junk. You could always go to a
74H10 version of the gate, which
has only a 6 nsec typical gate

Fig. 3. Integrated circuit and
LED layout . Resistors were
placed on end between 1C
packages to conserve space.

Part

Qty.

Price ea.

Total

Radio Shack Board
#276-154

1

$3.50

$3.50

74LS85

4

1.00

4.00

7474

1

.35

.35

7475

2

.50

1.00

74LS10

1

.25

.25

74121

1

.35

.35

7805

1

1.25

1.25

8-pos DIP switch

2

2.25

4.50

LED

10

.20

2.00

10k Resistor Vi W

17

.05

.85

Ik Resistor Vi W

10

.05

.50

100 uF 16 V Elect

1

.20

.20

Switch, Toggle SPST

1

2.00

2.00

.01 Disk caps

A

.05

.20

$20.95

Table 1. Parts list. The entire circuit was constructed on a Radio
Shack experimenter board with the standard 44-pin edge connec-
tor. The total price can be reduced if you have a well-stocked junk
box.

A0 □>

Al C>-

A2 O— -

A3 O-

13

La^-O

12

tvw-O

10

Vcc

GNO

74LS85

16

8

7475

5

12

74LSI0

14

7

7474

14

7

74121

14

7

AI2 O

02 O

SINGLE
SHOT

ARM \
CLOSED
FOR
CONT

Fig. 2. Logic diagram of the poor man's logic analyzer.

Microcomputing , October 1980 197

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delay. I did not try one, but that
would probably guarantee suc-
cess (if that’s possible), al-
though I doubt you’ll have any
trouble with the circuit as
shown.

For My Next Project

As far as enhancements to
the current design, I believe you
could build a similar circuit that
would provide for, say, 16 con-
secutive addresses once the
trigger address is recognized
and store them in a couple of
7489s, which are 16x4 RAMs.
Also, if you wanted to spend the
money, you could buy those
hexadecimal displays with the
latch and decoding all in one
package. These would make for
a nice display, but would in-
crease the cost of the project
significantly.

Did I Get My System Running?

If you are wondering whether
or not I got my system running
with the help of this analyzer,
the answer is yes! I set the ad-
dress trigger to an address in

the section of the monitor that
was supposed to run each time
a reset was pressed. I checked
that the program actually
passed through that point, as
well as if the data from the ROM
was correct.

I continued this until I found
the problem area to be the baud
rate measuring routine. I
checked the baud rate generator
board I had built and found it
was putting out a 1200 baud rate
even though I had it set for 600
baud. This was evidently too
high for the TIM program to
properly read. I corrected the
problem on the baud rate board,
set it to 600 baud, pressed reset,
and it printed all my register
contents and sat waiting for my
command.

I can attribute my success to
my poor man’s logic analyzer.
I’m sure I would have found the
problem eventually, but I’m also
sure it saved me a lot of valuable
time. . . much better spent try-
ing to devise ways to improve
my system, not merely getting it
to work!B

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tS Reader Service index— page 241

Microcomputing , October 1980 201

A Humanist’s Approach
To Computer Programming

You can tell a lot about a person by the programs he writes.

Dick Lutz

4802 Fifth Avenue

Pittsburgh PA 15213

I n some sense, the subtitle
of this article might be “A
Computerist’s Approach to
Human Programming.” That is,
the intention is to program you ,
the writer of computer programs
for the use and enjoyment of
yourself and others, so that
what you preparb to run on your
computer will also run effective-
ly in your mind— and in mine
should I have the occasion to
read one of your programs (or
worse, attempt to ddbug it).

“What,” you may ask, “is the
percentage in this idea?” Why
should you write programs so
that I can read them? Simply be-
cause unless you’ve never writ-
ten anything more complicated
than a counting program, you’ve
probably had the experience of
trying to figure out what in the
world you were trying to do in
one section or another of one of
your programs. Surely you’ve
puzzled over somebody else’s
poorly annotated program, won-
dering what in the world he had
in mind.

Is this a plea for documen-
tation? In part, yes. It’s time to
start writing programs for peo-
ple to read— not just machines.
My reasoning is that if you write
REMarks good enough to help
you understand your program
later, there’s at least a fighting
chance that if I encounter it, I’ll

eventually be able to untie the
knot it’ll put in my feeble
cranium.

But there’s even more to it. As
computerists, we’re on or near
the leading edge of something
that will become more and more
widespread in our society— the
use of electronic computers to
lighten the load and enlighten
life. That makes it particularly
important that we computerists
think like humanists in writing
programs. . .simply because
more and more people are going
to be trying to read them.

The exact approach is not
important— only that there be a
logical (humanly logical, please)
consistency to what you’re do-
ing, so that others can pick up
and read your style. Rather than
lecture about how to proceed,
let me tell you how I go about it,
and you can adapt my proce-
dures to those you’ve already
worked out for yourself.

PRGMBASE

I keep PRGMBASE handy. It’s
reproduced here. I load it
whenever I begin writing a pro-
gram in Microsoft BASIC. It not
only imposes form on what I
write, but it also helps me as I
write.

Program Writing Utilities

In lines 0-9, you’ll find some
utility items specifically written
for my hardware configuration.
By typing RUN/cr, I call line 1 in-
to action. It alternately expands
or contracts my Imsai VIOC
video output. This is convenient

because on my fussbudget
monitor, the 24 x 80 format oc-
casionally leaves doubt as to
whether I’m looking at 0, 8, 2 or 5,
all of which can look alike at the
screen’s edges.

Line 3 toggles video in and
out of the wraparound mode, so
RUN 3/cr gives me scrolling
whenever I need it. The 0-9 por-
tion of PRGMBASE is selected
for this duty because it simpli-
fies repeated call-up while
writing programs. These utilities
could as well be in the 65000
zone, except that it would take
more typing (“RUN 65302/cr”)
for each use.

Of course, once a program is
written and I have no further use
for these utilities, I just DELETE
0-10 before a final SAVE. But
there’s more.

Automatic Variable Index

Ever lose track of a variable?
It can be maddening to work for
hours to debug a recalcitrant
program, only to discover that
you’ve used variable CH as both
CHart and as CHange, and may-
be even as CHoice. With three
potentially overlapping assign-
ments, your program is sure to
stumble on a variable sooner or
later. I’ve made this mistake so
often that I now keep track of my
variables as I go along, using
the variables index built into
lines 7000-9700 of PRGMBASE.

It’s very easy, once you get
used to it. A variety of methods
are possible, but what works for
me is to take a hard-copy listing
of lines 7000-9700 as I begin.

Then I can see at a glance that
the K variables are indexed at
8100, and that variable KS would
be indexed at 8100 + 19, S being
the 19th letter of the alphabet.
Since I don’t remember that S is
letter #19, line 8900 reminds me.

When I’m about to use a new
variable, I determine what its
number would be in the in-
dex— but before I write the index
line for it, I LIST it. If it comes up
blank, I know I’m in the clear. If
not, I’ve saved myself some ex-
cruciating debugging. And
through the process of saving
the variables in this index, I’ve
helped myself and others to
decipher what my program is
supposed to be doing.

If it’s carefully planned, the
variable index itself can be used
to initialize variables, set default
values and to DIMension arrays
(see lines 8717, 8726 for ex-
amples). And as a final bonus,
this simplifies the DEFINT pro-
cess at the end of program
writing, since a glance at a sec-
tion will tell you immediately if
all R (or S, or B) variables are in-
tegers.

Incidentally, you’ll notice in
the index that LN is a reserved
variable, which means LiNe
(number). When I’m writing a
program section that later might
give me trouble— or if I’m fret-
ting over one that is already giv-
ing me fits — I just insert an extra
line: LN = (current line number).
Then I add the following line to
my utilities in the 0-9 section:

4 PRINT "BUGSPRAY NEEDED LINE”; LN;
:RETURN

202 Microcomputing, October 1980

By inserting G0SUB4 where I
suspect a program is running
amok, I get a readout of where
my problem may be. Again,
there is a variety of approaches
to this idea, and you can impose
your own method to make it
work best for you.

Program Index

PRGMBASE also provides a
program index, which simplifies
the work of somebody trying to
figure out what the program is
intended to do, as well as help-
ing me organize myself while
writing a program. So that I don’t
spend a lot of time figuring out
where to index a program sec-
tion, there’s a simple formula in
the program for deriving the in-
dex location from the program
line number, or vice versa:

INDEX - (PROG RAM LIN E/1 00) + 10000

or, in human terms, drop the last
two digits from the program line
number and add 10 to the left of
what remains. Program line
25500 becomes index location
10255. In reverse, it’s just a mat-
ter of dropping the 10 from the
head of the index number and
adding 00 at the end of the
resuit. Thus, index location
10025 refers to program line
(0)2500.

Program Structure

In a further sense, the way I
write programs in itself amounts
to an index. That kind of pro-
gram structuring is shown in
PRGMBASE in lines 10860 and
up. Once more, this is not just
useful to the poor schlemiel who
may have to figure out what I’ve
written, but to me while I’m
writing a program— particularly
when I must leave it for a few
days and want to return with
some notion of what I was do-
ing.

I use four (sometimes five)
routine levels:

DEITY rarely, In lines 0-9

REGAL in the 10 to 99 LNs

EXECUTIVE in the 3-digit lines

MANAGERIAL in the 4-digit lines

WORKER in the 5-digit lines

As a rule (but not without

This program was written in Microsoft
disk BASIC version 4.51; in the current
versions, 5.0, a space is required be-
tween GOSUB or GOTO and the line
number. That is, GOSUB9980 is illegal;
use GOSUB 9980 instead.

Program 1.

0 'later will jimp into program

1 PRINT CHR$(27);CHR$(67);

CHR$ (27 ) ; CHR$ (76 ) ;

CHR$(26); : STOP' video size

3 PRINT CHR$(27); CHR$(83)j:

STOP' scroll/wraparound switch
5 PRINT CHR$(26); ' clear screen

9 STOP' backstops utilities 0-9

10 •

98 STOP’ final program stop

99 •

1000 '

6999 *

7000 'VARIABLES INDEX

7001 'Var

9809

8214 *LN

8713 '0M

8726 QZ=1
8751 *01

r ar

TYPE

function

A. .01..

B. .02. .

c. .03. .

>..04

D..04..

:..05

E. .05. .

•..06

F..06..

;..07

G..07..

I. .08

H..08..

I. .09..

J..10..

K..11..

L. .12. .

.N

int

LiNe number

M..13..

N. . 14. .

). . 15

0..15..

P..16..

Q..17. .

>M

i

Quote Manip'

M 00(5,5)’

Oues array

:=i'

i

1-on, 0=off

>1

.III

var Quotient

R. .18..

S. . 19. .

T..20. .

U. .21 . .

r. .22

V. .22. .

f- -23

W..23..

X. .24. .

:..25

Y. .25. .

9697 RETURN 'from getting these values

9699 '

9700 'LINE LLISTER UTILITY

9702 PRINT CHR$(26)' clear screen

9703 CC=32:LN=1:CL=3:G0SUB9980'

With CC an ASCII blank (32),
call 9980 (position A print)
to place cursor at LN1, CL3,
to display:

9706 PRINT "NEXT > RUN \ to LList”

9709 CL=10:LN=2:00SUB9980'pos to pnt:

9710 PRINT "9770 ! Program Index"

9711 LN=3:OOSUB9980

9712 PRINT "9790 ! VARs Index"

9713 LN =4 : GOSUB 9980

9714 PRINT "9810 ! DEITY 0-9"

9715 LNs5:OOSUB9980

9716 PRINT "9830 ! RECAL 10-99”

9717 LN =6: GOSUB 9980

9718 PRINT "9850 ! EXECs 100-999”

9719 LN =7: GOSUB 9980

9720 PRINT "9870 ! MGRs 1000-6999”

9721 LN =8: GOSUB 9980

9722 PRINT "9890 ! subrs 10660-10999"

9723 LN =9 : GOSUB 9980

9724 PRINT ”9910 ! WRKRs 11000-"

9725 LN =10: GOSUB 9980

9726 PRINT "9930 ! this utility"

9729 PRINT CHR$(30); :S70P’

Await run command

9769 '

9770 'LList PROGRAM INDEX
9772 LN =2 : CL= 1 : GOSUB 9980 »

place cursor and
9774 PRINT " LISTING:'"

so that it covers the
menu item being run
9776 LN=3: GOSUB 9980 '

position cursor,
mark place with:

9778 PRINT "RUN NEXT> "

9779 LN=2:CL=1:GOSUB9980

9782 GOSUB 9990' skip 3 lines

9783 LPRINT "PROGRAM INDEX LISTING"

9784 LPRINT' skip 1 line

9785 LN =2: GOSUB 9980’

repark the cursor to spot
the "0k," on completion of
LList, at the RUN NE)(r>.

9786 LLIST 9999-10699

9788 STOP

9789 '

Remaining modules follow
the same pattern as
lines 9770-9788; see sub-
routines at 9980, 9990.

9790 'LIST VARIABLES INDEX

9794 LN=3:CL=1:G0SUB9980

9795 PRINT " LISTING:"

9796 LN =4: GOSUB 9980

9797 PRINT "RUN NEXT> "

9798 LN =3: GOSUB 9980

9802 GOSUB 9990

9803 LPRINT "VARIABLES INDEX"

9829

9849

LPRINT

10505 becomes 50500

LN =3: GOSUB 9980

10005

•

LLIST 6999-9699

10070

• 7000

VARIABLES listing

STOP

A =7100, B =7200,

A1=7151, B1=7251, etc.

'LIST DEITY LEVEL

10100

• 10000

this INDEX

LN =4 : CL= 1 : 00SUB9980

10107

• 10700+

suggested conventions

PRINT " LISTING:"

10699

•

LN =5: GOSUB 9980

10700

»

PRINT "RUN NEXT> ”

10709

•

LN =4: GOSUB 9980

10730

•SOME SUGGESTED CONVENTIONS

GOSUB 9990

10740

•

LPRINT "DEITY level”

10750

'Lnls

generally

LPRINT

ending

are used

LN =4: GOSUB 9980

in:

for:

LLIST 0-9

10760

• 0

stock entries used with

STOP

PRGMBASE regularly

'

10761

' 1

draft 11 of a prgm

•LIST REGAL LEVEL

(w/ 20-line spacing

LN=5:CL=1:O0SUB9980

to allow additions)

PRINT " LISTING:"

10772

• 2

draft 12

LN =6 : GOSUB 9980

(using the alternate

PRINT "RUN NEXT> "

20-line spacing)

LN =5: GOSUB 9980

10783

’ 3

draft 13 (revisions)

GOSUB 9990

10794

• 4

draft 4

LPRINT "REGAL LEVEL"

10805

’ 5

draft 5

LPRINT

10816

• 6

draft 6

LN =5: GOSUB 9980

NOTE: As new

LLIST 10-99

drafts come in, the old

STOP

lines deleted are not

'

re-used 'til needed;

'LIST EXECUTIVE LEVEL

they are simply erased.

LN=6:CL=1:G0SUB9980

10827

• 7

RETURNS

PRINT " LISTING:"

10838

' 8

temporary checklines

LN =7: GOSUB 9980

A last ditch stuff;

PRINT "RUN NEXT> "

treat as "extra" 'til

LN =6: GOSUB 9980

desperately needed

GOSUB 9990

10849

’ 9

spacer lines

LPRINT "EXECUTIVE LEVEL"

between prgm sections,

LPRINT

like 10859 below.

LN=6:OOSUB9980

10859

9867 LLIST 99-999 1086O

9868 STOP 10870

9869 '

9870 'LIST MANAGER LEVEL

9872 LN=7:CL=1 : GOSUB 9980
9874 PRINT " LISTING:"

9876 LN =8: GOSUB 9980

9878 PRINT "RUN NEXT> " 10875

9879 LN=7:00SUB9980
9882 GOSUB 9990

9884 LPRINT "MANAGER LEVEL"

9886 LPRINT :LN =7 :00SUB9980

9887 LLIST 999-6999 10881

9888 STOP

9889 ' 10885

9890 'LIST misc SUBRs in 10660-999

9891 LN =8 : CL=1 : GOSUB 9980 ^

9893 PRINT " LISTING:"

9895 LN =9: GOSUB 9980 10 891

9897 PRINT "RUN NEXT> "

9899 LN =8 : GOSUB 9980
9903 GOSUB 9990

9905 LPRINT "miscellaneous subrs"

9906 LPRINT: LN=8:OOSUB9980 10g01

9907 LLIST 10659-10999

9908 STOP

9909 '

9910 'LIST WORKER LEVEL

9911 LN=9:CL=1:G0SUB9980
9913 PRINT '• LISTING:"

9915 LN =10: GOSUB 9980 10902

9917 PRINT "RUN NEXT> "

9919 LN=9:G0SUB9980

9921 GOSUB 9990

9923 LPRINT "WORKER LEVEL”

9925 LPR INT : LN =9 : 00SUB9980

9927 LLIST 10999- ’ to end 10904

9928 STOP 10905

9929 '

9930 'LIST THIS UTILITY

9931 LN=10:CL=1 : GOSUB 9980
9933 PRINT " LISTING:"

9935 LN=1 : GOSUB 9980

9936 GOSUB 9990

9937 LPRINT "LineLLister utility"

9938 LPRINT

9941 LN =2: GOSUB 9980
9943 LLIST 9699-9999
9945 GOSUB 9990

9979 '

9980 'POSITION CURSOR to PRINT 10906

9982 PRINT CHR$(27); CHR$(61);

CHR$(LN+31); CHR$(CL+31);

CHR$(CC);' position cursor

and print CC (a blank in this
particular usage).

9984 RETURN

9989 ’

9990 'LSKIP 3 LINES subroutine
9992 LPRINT: LPRINT: LPR INT
9994 RETURN

9999 ’

10000 ' MASTER PROGRAM INDEX

to derive an index location for
a program line, drop the last 2
digits 4 add 10000

10001 ’ INDEX 2000 at 10020,

20000 at 10200,

25500 at 10255

10002 ' to turn an index number into a

prgm line number, drop first 2
digits 4 add 2 trailing zeroes

10003 ’ 10255 becomes 25500,

10021 becomes 02100, 10999

•PRCM STRUCTURE conventions
'Levels of operation:

Deity 1-digit linels

Regal 2-digit linels

Executive 3-digit linels

Managerial 4-digit linels
Worker 5-digit linels

'First digits always deal with
like matters, gosubbing thru
the levels making ever-finer
decisions 'til some worker-lvl
does actual processing.

'Thus, branching follows this
pattern, generally:

• 20- 30 REGALS gosub to

200- 300 EXECs which gosub

2000- 3000 MANAG'L, to
20000-30000 WORKERS , etc .
•RETURNS always "backstitch the
seam," so 20200-20297 RTNs
to the 2021+ range. That could
have a 2027 RTN to exec, or a
2030 gosub to 20300.

'Thus the following might be the
flow of a typical program,
with > 4 < indicating gosub
and return directions.

[Follow the arrows > right for
gosubs, left < for returns,
reading down. )

•The letters A-D indicate
routine and subroutine levels:

A = Regal
B = Executive
C = Managerial
D = Worker

• A B C D

• 10

20 > 200 > 2000 > 20000

< 20297
2030 > 20300

< 20397

2040

2050 > 20500

< 2077 < 20797
210 > 2100 > 21000

< 217 < 2197 < 21997

22 > 220

230 > 2300

2400 > 24000

<297 < 2997 < 29997

30

35*

41 > 410 > 4100

4200 > 42000

< 42997
4300 > 43000

< 4397 < 43997
440

450

460 > 4600 > 46000

< 46997

4700

4800 > 48000

10908 ' < 487 < 4897 < 48997

50

60*

98 final program stop

Microcomputing, October 1980 203

exception), the lower-numbered
lines are privileged to call the
higher-numbered lines as sub-
routines. This is why the
7000-9700 line numbers were
chosen as PRGMBASE’s vari-
able indexing section — be-
cause, simply, there are no
worker-level line numbers to
call, at 70000-99000, in most
systems running BASIC.

There are exceptions to the
calling convention because a
particular subroutine may be
useful from more than one pro-
gram level. This approach also
means that I can use the first
digit of any line number as a
clue to its task. All line numbers
beginning with 2, for example,
might direct introductory re-
marks to the user and offer
choices to be made by him.

In a top-down approach to
programming, you’d write the
DEITY level first, then the
REGAL, and so on. Although it
might violate the sensibilities of
the hardbit top-down devotee,
this method of program orga-
nization allows you to write and
place a tiny subroutine when a
neatly turned approach occurs
to you. . .and then to be sure it

works even before writing the
calling level.

Fig. 1 shows how the calling
convention works. It’s also
shown in PRGMBASE lines
10904 to 10908; if you adapt your
own version of PRGMBASE,
having this section in it will pro-
vide a quickly available remind-
er until this approach becomes
second nature to you.

LListing Made Easy

A final bonus of this system
of program writing is that stick-
ing with the calling conventions
means you can selectively pro-
duce really useful hard-copy list-
ings. In fact, PRGMBASE con-
tains its own Utility LineLLister
in lines 9700-9994. On RUN

9700/cr it generates a video
menu that looks like this:

NEXT

RUN

to LList

9770

Program Index

9790

VARs Index

9810

DEITY 0-9

9830

REGAL 10-99

9850

EXECs 100-999

9870

MGRs 1000-6999

9890

subrs 10660-10999

9910

WRKRs 11000-

9930

this utility

The utility then waits for com-
mands with video keeping the
place with its pointer, NEXT >,

at the next line to run for a top-
down listing. Of course, I take
the option of listing only what I
need for a given process. Using
this programming method, that
almost always means from one
level, say MGRs, through the
levels it calls. Also, since lines
400-499 will usually call only
sections in the 4000-4999 (and,
in turn, 40000-49999) portion, I
save myself much confusion in
figuring out what to list and
what to debug. . .and I cut down
the paper I have to haul around,
too.

Objections

As you might suspect, I’ve
discussed this approach to pro-
gramming with others who
spend hours looking at video
monitors and poking away at
keyboards. Some voice an ob-
jection that memory is costly,
and they don’t have any to
spare. My response is that it’s
getting cheaper, but even now
they can use the methods at the
start of programming, later
deleting excess parts or saving
one complete annotated copy of
the program and “stripping”
another for space consider-

ations. Furthermore, I maintain
that PRGMBASE can save mem-
ory by imposing code-saving
outline methods on program-
mers.

But the most frequent objec-
tion surprises me: “But then I
can’t use RENUMber to bail me
out when I run out of line
numbers!” Well, yes and no.
You can often RENUMber pro-
gram lines within the strictures
of this approach to program
writing. Unfortunately, if you
have to do an extensive renum-
bering job on a program, the pro-
gram index will be nearly
useless afterward. But if you
think about your programming
in a way that will help it all make
sense to a (human) program
reader later on, you probably will
not need the RENUMber option
very often.

It’s worth the thought, and the
time. It is aesthetic to write neat
programs for your personal
computer which, if appreciated
and observed, can lift your inter-
action with the machine to a
new level of elegance. Try it! It’ll
make your machine just a little
more human— not to mention
what it’ll do for you! ■

LEVEL:

LINES:

A

REGAL

10-99

EXECUTIVE

100-999

C

MANAGER

1000-9999

D

WORKER
10000 +

IOOO-
10650 =
INDEX

Note thot the more authority
a level has, the less likely it is
to "report bock" to o higher
authority before passing control
to another section ot the same
level.

No GOSUB out of 220 effectively
reserves 2200-2299 and 22000-22999
for later implementation.

|^2400^J «|^24000^J

1 297 |«- - .| 2997~~j* 1 29997 |

TO 30

Line numbers ending in 0 represent
a range starting at that number.
They GOSUB to a range represented
by adding one zero.

By convention , line numbersending
in 7 are RETURNS

4-

*0

450

Some EXECUTIVES never get MANAGERS
under them, some MANAGERS, no WORKERS
In o top-down approach, the option always
remoins to odd staff. Under these conventions,
staff line numbers are reserved automatically
when on EXECUTIVE or MANAGER level
"department" is created.

50

7000-

9999.

VARIABLE

INDEX

and

Line LLister

Fig. 1. Calling convention.

204 Microcomputing, October 1980

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v* Reader Service index— page 241

Microcomputing, October 1980 205

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COMPUTER INSTANT ADS ASSOCIATION

277 East 6100 South • Salt Lake City, Utah 84107

EH

Skylcs Electric Works

231 E South Whisman Road
Mountain View, CA 94041

206 Microcomputing , October 1980

Reader service index— page 241 Microcomputing, October 1980 207

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Goodies from GALACTIC

Specially Programs for

TRS-80 Model I - II - III

EDAS 4.0 (Editor/Assembler)

This is the highly acclaimed "USER ORIENTED" Assembler
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STOCK MARKET MONITOR

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INVENTORY MASTER

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MODEL II HOST I/O SYSTEM

From the original author of the TRS-80 HOST and TERM
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ULTRA TREK

This is an all new concept for this type of game, and
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Overlay Programming

Small memory space? Take a tip from IBM and try this memory-saving technique.

Robert A. Peck
1276 Riesling Terrace
Sunnyvale CA 94087

M any microcomputer users
start out on small systems
such as KIM, SYM, COSMAC
and D-2. These one-board BASIC
computers all have one thing in
common: a minimal amount of
memory space reserved for the
user program. They often allow
as few as 256 bytes of RAM
space for user access.

Even when we add the remain-
ing on-board memory to the
basic unit, we end up with be-
tween 512 bytes and 4096 bytes
of available space. When a com-
puter user runs out of on-line
memory space, regardless of
the size of the system being
used, he has various choices:

1. Purchase additional mem-
ory (with expansion power sup-
plies) and perhaps an adap-
tation for bus compatibility.

2. Sell off the “basic unit”
cheaply to a friend or a broker so
you can save money to buy a
bigger unit with more memory
already installed and rewrite
your programs to fit the new pro-
cessor.

3. Make the programs fit the
available memory space by tak-
ing advantage of your off-board
mass-storage device and the
use of an overlay program struc-
ture as described below.

Running out of RAM space
happens not only to the small
micro user, but also to all of the
rest of the processor users from
small systems to the giants.

These larger-system users use a
technique that could prove
useful to users of minimal
systems as well: the overlay
structure.

How the Big-Systems Users
Do It

This technique called overlay
is often applied to devices in
which a functional program
takes up almost all of the avail-
able memory-storage space. In
order to check out the opera-
tional characteristics of the de-
vice, reserve an area of the RAM
for the loading of the diagnostic
programs.

If the diagnostic program
storage area is small, an in-
terlinked chain of programs may
be called in to test each ma-
chine function, in turn, and to re-
port the results of that portion of
the tests. After this, the next
routine in the chain is read into
that same memory section as
occupied by its predecessor.
Then control is given to this next
program segment for its diag-
nostic operation.

It is called an overlay struc-
ture because the new diagnos-
tic program entirely erases and
replaces the program that pre-
cedes it. Each program is stored
and executed from only that
segment of the memory re-
served for the storage of the
diagnostic routines.

When the diagnostics are
completed, the machine allows
the option of either running
more diagnostics or returning
control to the master program.
That master program would, in
this case, have taken up most of
the available RAM space, and

the troubleshooting diagnostics
would have taken up relatively
little space.

There are several reasons for
this:

1. The unit is designed so that
it works “perfectly” most of the
time.

2. The master program, for
economic reasons, takes up
most of the space in that there is
little reason to install any more
memory than absolutely needed
for normal operation.

3. The diagnostic routines can
be made simple enough so that
each may check a small number
of basic machine functions.

4. Depending on the capabil-
ities of the mass-storage device
associated with it, there may be
little reason to limit the total
number of diagnostic routines

T"

312 BYTES OR LESS
(DENOTED "X" BYTES
PER SEGMENT), LIMITED
BY AVAILABLE USER
RAM SPACE

"x“ BYTES OR LESS

T

"X" BYTES OR LESS
1

Fig. 1. The initial step— program
segmentation.

loaded one at a time, except to
use sufficient programs to have
tested all desired basic func-
tions of the device.

Therefore, .for the machine
type, which is described above,
when power is applied, we
would load the master program,
which runs all of the basic func-
tional items in the machine, in-
cluding monitoring the control
switches. If a diagnostic routine
is desired, that routine is loaded
into a separate segment of RAM
and is executed. After this, con-
trol passes again to the main
program, which may load an-
other diagnostic routine or
simply continue on with its nor-
mal operating sequence.

As stated, the device we ex-
amined earlier used most of the
RAM space for the storage of
the functional program and only
a small amount for the diag-
nostic routines. The small-sys-
tem user, however, is more likely
to reserve a maximum portion of
his RAM space for the program
material.

Program Structure

As an initial plan for fitting a
large program into a small
space, we must first consider
structuring the program as
noted in Fig. 1. Each of the seg-
ments should be capable of fit-
ting individually into the avail-
able user RAM space.

Note the linear flow between
the segments in Fig. 1. The dia-
gram is intended to show the
need for these segments to
operate independently. Using
the logic outlined in Fig. 2, we
can see that a relatively small
control program can be used to

208 Microcomputing, October 1980

LDA

NXTSEG

;load acc with next segment ID number

STA

TAPEID

;store in tape ID byte search compare area

JSR

TPLOAD

;call tape-load subroutine (part of monitor)

JMP

STARTX

;jump to the starting point of this routine
;(not the next routine)

Example 1. A typical link call sequence.

oversee the loading and execu-
tion of a considerably larger
segmented program.

Fortunately, many manufac-
turers of single-board com-
puters write their tape-load pro-
grams as subroutines within
the monitor program. Although
these routines are normally
called by the monitor and return
control to the monitor, we can
use them within our programs
and regain control from the sub-
routines after the tape load has
been completed. Thus, we can
effectively reduce the size of our
control program by efficient use
of the monitor subroutines.

There may be occasions,
however, when even the relative-
ly small size of the control pro-
gram tends to get in the way.
This could happen if there is a
need to transfer a large number
of variables between program
segments. This forces us to re-
serve more of the control pro-
gram space for common area
storage.

Linking Program Segments

If control program space is in
a squeeze, we could, instead,
place the cassette subroutine
call linkage within each of the
program segments. Thus, each
individual segment would have
duplication of the tape-load sub-
routine call, but we would have
possibly reserved more space
by this means for the passing of
variables between program seg-
ments.

As an example, let’s look at a
typical tape-load routine linkage
that might be contained within
a single program segment. It
could be placed at the logical
end of the segment because it is
considered the exit point from
that segment and the linked en-
try to the next segment (see Ex-
ample 1). The last line, at first
glance, may be a little difficult to
understand, but with a little ex-
planation it is really quite clear.

Since this is an overlay struc-
ture, each program segment
completely replaces the original
segment that occupied that
RAM space. When we jump to
the tape-load subroutine, the
program counter contents are
pushed onto the stack. When we
complete the tape load, the
return address is popped off the
stack and reloaded into the pro-
gram counter.

At this point, the processor
executes the instruction cur-
rently residing at the location
immediately following the loca-
tions formerly occupied by the
call to the tape-load subroutine.
So we went off to a tape-load
routine and when we came back
to the area originally occupied
by the calling program, we were
actually jumping into a new pro-
gram that has since replaced it
in that same memory space.
Therefore, when we return, we
will execute a jump to the start
location of the newly loaded
segment. By maintaining the
same structure in each of the

Fig. 2. The overlay control pro-
gram structure.

0200

Segment 3

0200

Segment 4

Program

Program

03F5

LDA 04

03F5

LDA 05

03F7

STA TAPEID

03F7

STA TAPEID

03FA

JSR TPLOAD

03FA

JSR TPLOAD

03FD

JMP BEGIN03

03FD

JMP BEGIN04

Example 2.

segments, however, we can
always assure that the pro-
cessor knows where to find its
next instructions.

To demonstrate this, let’s put
some numbers with the example
above (see Example 2). After we
have executed the main body of
segment 3, we load the accumu-
lator with the value of the next
segment’s ID code at 03F5. Then
at 03F7 we store it in the byte
area where the tape-load routine
looks for a comparison to the
tape ID being read. Now, at
03FA, we jump to the tape-load
subroutine from segment 3. This
will load segment 4 into loca-
tions 0200-03 FF, where segment
3 was before.

When we execute the return

from the tape-load subroutine,
the processor will execute the
instruction at 03FD. This in-
struction, you will note, is now a
segment 4 instruction, not seg-
ment 3, due to the overlay that
has occurred. Therefore, within
that segment 4, the instruction
indicates a jump to the begin-
ning of segment 4 as other seg-
ments will, in this same area, in-
dicate a jump to their own start-
ing areas.

Thus, if all of the program seg-
ments are constructed in this
manner, we will only be limited
by the adaptability of the pro-
gram to this type of structuring.
For the memory-limited pro-
grammer, this method may
prove to be useful. ■

Jrimcattonal

Haitian re . ,

professionals, _

HI RES TITRATION JltO*

HI-RES TITRATION is a simulation of an acid base titration using
the Apple high-resolution color graphics. The program was written
for use as a prelaboratory preparation and practice. It is effective
as a lecture demonstration or for use by individual students. The
program was written for high school use, but it is also useful for
college chemistry classes.

32 K Applesoft with Disk $19.95

RETAILING MATH

RETAILING MATH is a computer assisted instruction in the
fundamentals of pricing mathematics. Lessons and reviews deal-
ing with the mark-up equation, mark-up percentage and deter-
mining retail and cost prices are reinforced thru interactive
exercises after each lesson by vocationally certified instructions.
48K Applesoft with Disk $39.95

EDUCATIONAL CHARADES

EDUCATIONAL CHARADES is an age-long game modified for
classroom use. The teacher can create charade files relative to the
current subject being taught.

32 K Applesoft with Disk $19.95

APPLE-GRAMMER requires 32K in Applesoft and a disk drive . . .

$19.95

TEACHERS’ AIDE I with Multi-Choice format requires 32K in
Applesoft and a disk drive 1 9.95

TEACHERS’ AIDE II with True and False format requires 32K in
Applesoft and a disk drive $19.95

38437 Grand River# Farmington Hills, Ml 48018
(313)477-4470 ^ 156

Dealer’ Inquiries Welcome

Microcomputing, October 1980 209

A Roundoff Function in Applesoft

Keep your numbers at a manageable length.

Barton M. Bauer s, Jr.
30 Hillock Drive
Wallingford, CT 06492

W hen writing programs in Applesoft,
you will occasionally need to round
off an answer to a specified number of
decimal places. Example 1 shows a simple
function that will handle almost all of your
round-off requirements.

If you place this function at the beginning
of your program, you need only to set XQ
equal to the number of decimal places you
wish to have in your final answer and use
the statement VAR = FN RD(VAR), where
VAR is the name of any real (floating-point)
variable in your program.

How the Function Works

Review the function and dissect it into its
constituent elements. The function breaks
down into six pieces:

First, (10 A XQ) raises the value ten to a
power that is the same number as the
number of decimal places you want in your
answer.

Second, X* multiplies the result of (10 A
XQ) times the variable you wish rounded.

Third, + .5 adds one-half to this result.

Fourth, INT takes the integer representa-
tion of the result of step three.

Fifth, (10 A ( - XQ)) raises the value ten to
a power that is the negative equivalent of
the number of decimal places you want in
the answer.

Sixth, multiply the results of step five by
the results of step four.

Consider the example 4.457453. We will
use this number to demonstrate how FN
RD(X) works. Assume for now that you want
this number rounded to two decimal places.
Using the six steps above, the function
described will calculate the correct value as
follows:

XQ will equal 2, the number of decimal
places you want in your answer. Therefore,
(10 A XQ) will equal (10 A 2), or 10 squared,
which is 100.

The variable X is equal to 4.457453. Note
that X is only a phantom variable, to be
replaced by the actual variable you use.
Multiplying X by the result of step one, 100,

DEFFN RD(X) = INT(X * (10 AXQ) + .5) *(10 A(-XQ))

Example 1.

gives us 445.7453.

To the result of step two we add .5, so our
new value is 446.2453.

By taking the integer value of this
number, we will get 446.

(1 0 A ( - 2)) (remember, XQ was set to 2) is
the same as 1/(10 A 2), which is equal to
1/100, or .01.

Multiplying 446*.01, we get the final
answer: 4.46.

Not Perfectly Round

While this function will provide accurate
rounding in almost all of your programs, it is
not 100 percent perfect. Some values, when
internally represented in your computer, are
pre-rounded: the actual value that FN RD(X)
sees when it starts its work is not the same
number that was keyed in. This will cause a
slight under- or over-rounding, but it is not
the fault of the function. Indeed, I have
worked with FORTRAN programs and have
written similar rounding functions and have
encountered similar minor rounding dif-
ferences for some values.

You should therefore carefully consider
whether or not an occasional rounding dif-
ference is acceptable. If it is not, then you
should further question whether or not any
rounding is appropriate for that problem. II

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210 Microcomputing, October 1980

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for Apple, Commodore, TRS-80, Atari

Call TOLL FREE - 800-421-0347

Hardware for Apple, Commodore, Vector -CALL

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CORVUS 10 MEGABYTE DISK DRIVE $4649

PASCAL LANGUAGE SYSTEM p

GRAPHICS INPUT TABLET V-

DISK II with CONTROLLER CARD -

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APPLE SOFT II FIRMWARE CARD 1 *

INTEGER FIRMWARE CARD I

PARALLEL INTERFACE CARD L.

SERIAL INTERFACE CARD -

COMMUNICATIONS CARD I

SERIAL INTERFACE CARD

SUP-R-MOD RF TV MODULATOR 24

SUP-R-TERM 80 col CARD 348

DAN PAYMAR Lower case kit 44

SVA 8" DISK CONTROLLER CARD 348

CtS ARITHMETIC PROCESSOR CARD. 348

CLOCK/CALENDAR CARD 238

INTROL X-10 SYSTEM 238

SUPER TALKER SPEECH SYNTHISIZER 258

ROMPLUS CARD w/KEYBD FLTR 17e

HEURISTICS SPEECHLINK 2000 224

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ALF MUSIC SYNTHISIZER 244

SSM A10 CARD (KIT) 128

SSM A10 CARD (ASSEMBLED) 189

NOVATION CAT MODE M 158

CCS GPIB IEEE INTERFACE 268

MICROSOFT Z-80 SOFT CARD w/CP/M 348
MICROWORKS DS— 65 DIGISECTOR. . 348

ROMWRITER 158

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CCS PROGRAMMABLE TIMER MODULE 158
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ASTROAPPLE. Software Factry 15.00

AUTOCHECKERS, Programma Inti 15.95

BITS. Periph Unltd 34.95

BABBLE. Software Factry 15.00

BASEBALL, Muse 14.95

BATTLESHIP COMMAND. Quality Sftw 14.96

BATTLESTAR 1, Programma Inti 15.95

BAZOOKA. Programma Inti 15.95

BEST OF BISHOP. Softape 39.95

BLOCKADE. Personal S/W 14.96

BOWLING. Apple 15.00

BRAIN GAMES. Creative Comp 7.95

BRIDGE CHALLENGER. Personal S/W . 14.95

BRIGHT PEN. Softape 34.96

BUSINESS/FINANCE, Programma Inti 19.95

CAI PROGRAMS-D. Creative Comp 14.95

CASTLE ADVENTURE. Programma Inti 15.95

CCA DATA MGMT . Personal S/W . . 100.00

CHECKBOOK. Apple 20.00

CHECKBOOK. Programma Inti 34.95

CHECKBOOK KING-C. Personal S/W 19.95

CHECKER KING-C. Personal S/W 19.95

CHECKER KING-D. Personal S/W 24.95

CLOWNS & BALLOONS. Programma 15.95

COMPUMATH. Edu Ware 39.95

COMPUREAD. Edu Ware 24.95

CRAPS. Softape 14.95

DANS DISK. Periph Unltd 24.96

DART ROOM. Programma Inti 15.95

DATA MANAGER. Hayden 49.95

DATABASE. Programma Inti 19.95

DATABASE II. Programma Inti 29.95

DATABASE MAIL-D. Programma Inti . 29.96

DATAMOVER. Apple 7.50

DDU & SDC. Periph Unltd 39.95

DEPTH CHARGE. Programma Inti 15.95

DISASSEMBLER. Microproducts 34.95

DOW JONES. Apple 50.00

DUAL RACE. Systems Design 16.95

EARTHQUEST-D. Programma Inti 19.95

EASY WRITER. Personal Softwr 99.95

ELECTRIC CARD FILE. Softape 19.95

ELECTRIC CRAYON. Muse 17.95

ELEMENTARY MATH. Muse 39.95

ENERGY AUDIT-C. Instant S/W . 80.00

ENGINEERING MATH-1. Hayden 14.95

ESCAPE. Muse 12.95

FASTGAMMON-C. Quality Softwr 19.95

FASTGAMMON-D. Quality Softwr 24.95

FILE HELPER. Baclan 49.00

FINANCE PACK. Apple 25.00

FLASH CARDS. Programma Inti 9.95

FLIGHT SIMULATOR. Sub Logic 25.00

FOOTBALL. Programma Inti 9.95

FORM LETTER. Periph Unltd 24.95

FORTE. Softape 19.95

FORTH. Softape 49.95

FRACAS-C. Quality Softwr 19.95

FRACAS-D. Quality Softwr 24.95

GALACTIC CONFLICT. Programma Inti 15.95

GAME PLAY w/BASIC. Hayden 9.96

GAME PLAY w/BASIC 2. Hayden 9.95

GAME PLAY w/BASIC 3. Hayden 9.95

GAMON GAMBLER-C. Personal S/W. 19.95

GAUNTLETS. Programma Inti 99.95

GENERAL MATH-1. Hayden 14.95

GLOBAL WAR. Muse 17.95

GOBLINS. Programma Inti 15.95

GRADE BOOK Creative Corp 24.95

GRAPHIC UTILITIES. Personal S/W . . . . 14.95
HI RES ADVENTURE #1. On Line Syst 24.95

HIRES PLAYGROUND. Systems Design 24.96
HOME ACCOUNTING-C. Programma Int 9.95
HOME ACCOUNTING-D, Programma 15.95

HOUSEHOLD FINANCE. Programma 24.95

HOUSEHOLD INVENT . Programma . . 24.96
INSTANT LIBRARY-C. Softape 39.95

INSTANT LIBRARY-D. Softape-39.96

JOHN S DEBUGGER. Broderick 35.00

LASER TURRET, Programma Inti 9.95

LISA. Programma Inti 34.95

MAIL LIST. Periph Unltd 39.95

MATCHWITS. Programma Inti 9.95

MATH TUTOR 1. Instant S/W 7.95

MATH TUTOR 2. Instant S/W 7.96

/MICRO.

BUSINESS WORLD

15818 Hawthorne Blvd iS 248
Lawndale, CA 90260 < 213 ) 371-1660

MATRIX INVERT-C. System Design ... 13.96

MAZE GAME. Muse 12.96

MEMO CALENDAR. Periph Unltd 29.95

MICRO INFOSYSTEM. Muse 99.95

MICROCHESS. Personal S/W 19.96

MICROCHESS-C. Apple 20.00

MICROCHESS-D. Apple 25.00

MICROGAMMON. Softape 14.95

MINI LEDGER. Programma Inti 59.95

MINI LEDGER-D. Programma Inti 59.95

MISSION IMPOSSIBLE. Creative Comp 14.95

MONITOR-D, Programma Inti 49.95

MORTGAGE, Instant S/W 7.95

MULTIPLE REGRESSION, Systems D . 24.95
ORIGINAL ADVENTURE-D. Creative Cp 24.95
OUTDOOR GAMES. Creative Comp. 14.95

PAD. Datasoft 19.50

PITS. Periph Unltd 30.00

PUMP. Periph Unltd 25.00

PARCHESI. Programma Inti 6.95

PERCEPTION l.ll.lll. Edu Ware 19.96

PERPUTUAL CALENDAR. Programma 9.95

PHASOR ZAP, Programma Inti 15.95

PINBALL Programma Inti 15.95

PIRATE ADVENTURE. Creative Comp . 14.95

POWER EDITOR. Programme Inti 15.95

PRO GOLF. Softape 12.95

PROGRAM EDITOR. Synergistic 40.00

PROGRAMMING AID. Dakin 5 39.95

PROGRAMMING AID 2. Dakin 5 49.95

QUARTER HORSE RACE. Programma 6.95

RAM TEST TAPE. Apple 7.50

ROCKET PILOT. Softape 12.95

SARGON 2, Hayden 27.00

SARGON-C. Hayden 19.95

SARGON-D. Hayden 34.95

SCORPION ATTACK. Programma Inti . 15.95

SCREEN MACHINE. Softape 19.95

SHELL GAMES. Apple 30.00

SINGLE DISK COPY. Periph Unltd . . 19.95

SKEETSHOOT. On Line 14.95

SOLITAIRE. Programma Inti 15.95

SPACE. Edu Ware 29.95

SPACE II. Edu Ware 24.95

SPACE SHUTTLE LANDING. Harvey . . 15.00
SPACE/SPORTS GAMES. Creative Cp 14.95

SPYTREK. Programma Inti 15.95

STAR WARS. Softape 12.95

IF YOU DON'T SEE IT HERE. CALL
US. WE CARRY EVERYTHING FOR
APPLE. TRS-80. COMMODORE.
VECTOR. ATARI. SORCERER.
TEXAS INSTRUMENTS. AND
MORE)

STATISTICS, Programma Inti 19.95

STATISTICS. Edu Ware 17.95

STIMULATING SIMULATIONS.

Personal S/W/ 14.95

STOCK MARKET. RTR 79.95

SUPER TEXT. Muse 100.00

SUPERCHIP. Eclectic 100.00

TALKING CALCULATOR. Softape 12.95

TALKING DISK. Programma Inti 19.95

TEXT EDITOR. Periph Unltd 59.95

THE CASHIER. Apple 250.00

THE CONTROLLER. Apple 625.00

THE SOURCE Periph Unltd 25.00

THE SOURCE. TCA 29.95

THE TYPESETTER. Programma Inti . 29.95

TIC TAC TALKER Softape 19.95

TIME CLOCK. Programma Inti 6.95

TIME TREK. Personal S/W 14.95

TINY PASCAL. Programma Inti 49.95

TRAPSHOOT. On Line 19.95

TRIVIA )[. Prooramma Inti 15.95

TURF ANALYSIS. Systems Design 21.95

TYPE TRAINER. Programma Inti 15.95

TYPING TUTOR. Microsoft 14.95

UNCLE SAM, Muse 12.95

UPDATES Periph Unltd 39.95

VISICALC. Personal S/W 150.00

VOYAGER EXCURSION. Programma 15.95
WEIGHT PLOTTER. Programma Inti 19.95
WHATSIT. Computerheadgr 125.00

WINDFALL. Edu Ware 19.95

CALL US TOLL FREE
FOR NEW CATALOG
OF ACCESSORIES &
SOFTWARE 800-421-0347

PET

ACCESSORIES

Commodore Dual Floppy Disk Drive $1,285.00
Second Cassette— from Commodore . 95.00

Commodore PET Service Kit 30.00

Beeper— Tells when tape is loaded 24.95

F>etunia— Play music from PET 29.95

Video Buffer— Attach another CRT 29.95

Combo— Petunia abd Video Buffer 49.95

TNW Bi-Dir RS-232 printer S-face 229.00

KIM A (A Single Board Computer

from Commodore) 179.00

CMB 8050 Dual Drive Floppy Disk . . 1,695.00

CBM Modem 395.00

CBM Voice Synthesizer 395.00

PET TO IEEE Cable 39.95

IEEE TO IEEE Cable 49.95

KIM1 & Power Supply Package Special 200.00

PET

SOFTWARE

ACTION. Soundware $9.95

ACTION GAMES. Creative Comp 7.95

ALPHABET. Commodore 9.95

AWARI. Programma Inti 9.95

BACKGAMMON. Commodore 9.95

BACKGAMMON. Hayden 10.95

BASIC BASIC. Commodore 14.95

BASIC FINANCE. Commodore 24.95

BASIC MATH. Commodore 29.95

BATTER UP. Hayden 10.95

BATTLESHIP. Programma Inti 9.95

BLACKJACK. Commodore 9.95

BLOCKADE. Programma Inti 9.95

BLOCKADE. Personal S/W 14.95

BOWLING. Commodore 9.95

BRIDGE CHALLENGER. Personal S/W . 14.95

CHASE. Programma Inti 9.95

CHECKBOOK. Commodore 24.95

CHECKER KING. Personal S/W 19.95

CHECKERS. Instant S/W 7.95

COSTING. Commodore 19.95

DATA BASE UTILITY. Commodore . . 24.95

DEPTH CHARGE. Programma Inti 9.95

DIET PLAN. Commodore 14.95

DISASSEMBLER. Commodore 24.95

DOW JONES. Instant S/W 7.95

DUNGEON OF DEATH. Instant S/W . 7.95

GALAXY GAMES. Commodore 9.95

GAME PLAY w/BASIC. Hayden 9.96

GAME PLAY w/BASIC 2. Hayden 9.95

GAME PLAY w/BASIC 3. Hayden 9.95

GRAPHIC GAMES #1. Creative Comp . 7.95

GRAPHIC GAMES #2. Creative Comp .7.95
GRAPHIC UTILITIES. Personal S/W 14.95

GRAPHICS. Commodore 9.95

GUESS A SENTENCE. Commodore . . 29.96

HANDS ON BASIC. Commodore 14.95

HOME ACCOUNTING, Programma Inti. 9.95

LOGIC #1. Creative Comp 7.95

LOGIC #2. Creative Comp 7.95

MACHINE LANGUAGE. Commodore 9.95

MAYDAY. Hayden 9.95

MICROBASEBALL. Hayden 9.95

MICROCHESS. Personal S/W 19.95

MONITOR. Programma Inti 6.95

MORTGAGE. Instant S/W 7.95

MORTGAGE. Commodore 14.95

NUMBER GAMES. Creative Comp 7.95

NUMBER REVERSAL. Commodore 9.95
ON THE HOUSE. Commodore 9.95

PERSONAL ACCT’NG . Programma Inti 19.95

PET SHOW. Commodore 9.95

PIRATE ADVENTURE. Creative Comp . . 14.95
PROJECTILE MOTION. Commodore 19.95

REALTY. Commodore 59.95

RHYMING. Commodore 9.95

SERIES/PARALLEL. Commodore . 19.95

SLOT MACHINE. Programma Inti 6.95

SOME COMMON BASIC PROB-D.

Osborne & Assoc 9.96

SPACETALK. Commodore 9.95

SPACETREK. Commodore 9.95

STATISTICS. Commodore 29.95

STOCK PROTFOLIO. Commodore 24.95
STRATHCLYDE BASIC. Commodore 14.95
TARGET PONG. Commodore 9.95

TIME TREK. Personal S/W 14.95

TREK X. Instant S/W 7.95

TURF & TARGET. Instant S W 7.95

USER PROT COOKBOOK. Commodore 9.95
UTILITIES Smithware 7.95

VIDEO CHECKERS. Compuquote 14.95

WORD PROCESSING 2 Commodore 99.95
WORD PROCESSING 3. Commodore 199.95
WORLD CLOCK. Commodore 9.96y

Clock Control Board

Mark A. Schimelman, M.D.
255 Townhouse
Hershey PA 17033

T he TRS-80 is a great com-
puter . . . almost. The people
at Tandy Corporation did a good
job of building an efficient, re-
liable machine at low cost. They
did not, however, put everything
that they could have into that
handsome case to make it the
most desirable machine on the
market.

Some of the more commonly
recognized omissions include
the lack of lowercase char-
acters, the lack of standard TV
video modulation, the inability
to include Level I and II ROMs in
the same machine and a rel-
atively slow clock for micropro-
cessor operation.

Fortunately, hardware buffs,
being compulsive creatures,
cannot stand such a vacuum.
They have created a whole
library of solutions— some of
which are elegant in concept
and function— to each of these
problems. I recently purchased
one such elegant device, the
TRS-80 Clock Control Board,
produced by William Archbold,
106 Snyder Dr., Mather AFB CA
95655.

I mailed off my $14.95, be-
cause Bill promised in his ad
that the user could control the
clock rate with simple Level II
commands and change clock
rates without destroying resi-
dent programs (a problem I had
with previous modifications).
My kit arrived promptly eight
days afterward and included a
clock control board, instruction
manual, hookup wire and dou-

Speeds up your TRS-80. . . elegantly.

ble-sticky pads for mounting in
the computer case.

Control Board

The clock control board is a
professional-quality 2Vz x V/t
inch double-sided PC board with
four ICs, a resistor and a
capacitor already preas-
sembled. There are nine clearly
labeled holes for the connection
of the board to the motherboard
via jumper wires.

The manual is simple and
clearly written with a good dia-
gram showing proper connec-
tion points (see Fig. 1) and a
schematic of the control board

Z56, pin 8, is cut. Total instal-
lation time was one hour, which
included double-checking the
wiring twice. The board worked
perfectly the first time.

When the computer is pow-
ered up, the control is auto-
matically set to the normal 1.77
MHz rate. To change the rate to
2.66 MHz, all you have to do is
type OUT 254,1 ENTER; to
change back to 1.77 MHz, type
OUT 254.0 ENTER. This control
statement can be part of a pro-
gram or entered at any time via
the keyboard.

As you might imagine, this
adds a new measure of flex-

utilized either mechanical or
electronic switches to switch
clock rates. The problem was
that the switch often occurred
at some random point in a
microprocessor cycle, leaving
the processor in limbo so that by
the time the rate settled at a new
frequency, the microprocessor
was lobotomized. The user then
had to power-down and repow-
er-up to sync everything again.

None of that is necessary
with the Clock Control Board
since it is controlled by an OUT
instruction and, hence, always
occurs between microprocessor
instructions. Thus, you have

circuit.

Assembly consisted of cut-
ting the hookup wire to appro-
priate lengths as described in
the manual and soldering them
first to the clock control board
and then to the appropriate
points on the motherboard.
Finally, a jumper connection
was made between Z43, pin Z,
and Z56, pin 14. The trace from

ibility in programming control.
Cassette tapes can be read or
written at either clock rate, giv-
ing effective baud rates of 500 or
750. Computer graphics and
computational time can be cut
by one-third as well, all under
complete computer control.
This is truly elegant design and
engineering!

Previous clock modifications

clock rate control under com-
plete computer control without
cutting any more holes in the
computer case.

As you may have surmised, I
am delighted by the TRS-80
Clock Control Board. It is a
simple-to-install, easy-to-under-
stand kit that does what it
claims to do. I recommend it
highly . . . good job, Bill! ■

212 Microcomputing , October 1980

NOW PRINT APPLE®

$ 795 .

HIRES - GRAPHICS NORMAL,
INVERSE, IN 2 SIZES.

TX-80 PRINTER

by

THE TX-80 MATRIX PRINTER ^ GRAFTRAX

SPEED: 58 LPM, 125 CPS

INTERFACES: Parallel standard IEEE 488 and serial RS-232
optional, (Apple type parallel card and
cable s 99.)

CHARACTER SET: Full 96 Character ASCII Set (upper and
lower case with expanded print).

PRINT HEAD: 100 x 10 6 character life expectancy.

GRAFTRAX OPTION* full dot addressable graphics (480 dots/
line) with Automatic print head protec-
tion on dense pictures plus form feed
and skip over perforation.

FREE! APPLESOFT- WARE for graphics dump included

* UPDATE EARUER TX-80’s TO GRAPHICS for $99.

Masterchrage S Visa O.K.

DEALER INQUIRIES INVITED ^ g7

Computer Comer of New Jersey

439 Rt 23, Pompton Plains, N.J. 07444 (201 ) 835-7080

PRICES SUBJECT TO CHANGE

You may love Wayne Green . . . you may hate him . . . but you
have to admit he has vision. And that vision created 80
Microcomputing— the only major publication devoted to
today’s largest selling computer.

80 Microcomputing is not just any computing magazine . . . it’s
a magazine written for the users of Tandy’s TRS-80*, a maga-
zine written to tell you the truth about it. Wayne Green has
never been one to mince words and so 80 Microcomputing tells
you the good things about the TRS-80* and the not so good. 80
Microcomputing also has reviews of compatible equipment,
programs and applications, plus users reactions that let you
know how the TRS-80* works and what it can do. Also you can
save hundreds of dollars on equipment by buying what you
know is right. And of course, 80 Microcomputing has the
editorial fireworks from Wayne that the industry has come to
expect.

So subscribe to 80 Microcomputing . . . the industry’s only ma-
jor publication for your computer ... the TRS-80*.

Circle 60 on the Reader Service card for a subscription
form ... or call use at 800-258-5473.

‘TRS-80 is a trademark of Tandy ^ 60

iX 291

COMPUTER
FORMS KIT

EACH KIT CONTAINS:

Samples, Prices, Order Form,

4 Checks, 2 Statements, 2 Invoices,
Programming Guides.

We specialize in small quantities, low prices.
500 CHECKS ONLY $29.95

SEND COUPON, CIRCLE BINGO or
PHONE TOLL FREE
1 + 800 - 225-9540

FAST SERVICE — It is our policy to ship within 6 working
days following our receipt of your order. CODE 46 1

Name

Address

State, Zip

NEW ENGLAND BUSINESS SERVICE, INC.
GROTON, MASS. 01450

Reader Service index— page 241

Microcomputing , October 1980 213

Dealers: Listings are $15 per month in prepaid quarterly payments, or one yearly payment of
$150, also prepaid Ads include 25 words describing your products and services plus your com-
pany name, address and phone (No area codes or merchandise prices, please ) Call Marcia at
603-924-7138 or write Kilobaud Microcomputing, Ad Department, Peterborough, NH 03458.

Kingston, PA

El Monte, CA

Ohio Scientific specialist in the San Gabriel
valley serving greater Los Angeles Full prod-
uct line on display. Specializing in business
computers In-house service. Custom pro-
gramming. Terminals. Printers Open Mon-
Sat, 9 AM-7 PM Computer & Video, 3380
Flair Dr., Suite 207, El Monte, CA 91731,
572-7292.

San Jose, CA

Bay area's newest computer store Featuring
the new Texas Instruments Tl 99/4 home &
business computer. Software for TRS-80, Ap-
ple, PET, etc Magazines Hobbi-Tronics, 1378
S. Bascom Ave., San Jose, CA 95128, 998-1103.

Santa Barbara, CA

Complete computer systems for business and
personal use. Classes, seminars, word process-
ing supplies, books, magazines. Computers
Plus, 1827 State St., Santa Barbara, CA 93101,
963-4542.

N. Hollywood, CA

Wholesale prices to dealers & computer club
members! Anadex, Atari, Base-2, Centronics,
Emako, Godbout, Hazeltine, Lobo, Microp-
olis, MicroPro, NEC, Okidata, Paper Tiger,
Soroc, Tarbell, Televideo, Tl, Vector Graphic,
Zenith & others. Patio Computer Sales Co.,
5437 Laurel Canyon Bl.,#208, N. Hollywood,
CA 91607, 762-0020.

For Sale: One Gimix computer nearly new,
excellent condition. 6800 CPU card, 16K
static memory card (Gimix). $800. Paul
Lamar, 123 S. Juanita St., Redondo Beach,
CA 90277. Work 213-374-1673, home 213-
316-8351.

For Sale: Smoke Signal Broadcasting disk
controller card, with the following software:
on 8” floppy disk, text editing system, disk
file BASIC and mnemonic assembler. $250.
Paul Lamar, 123 S. Juanita St., Redondo
Beach, CA 90277. Work 213-374-1673,
home 213-316-8351.

Trade ham station for AIM 65. Also trading
O.S.I. programs, etc. Write to Henry A.
Etchason, Box 147, Sage, AR 72573.

TRS-80 Mod. I, Level I with Expansion In-
terface & 10 key, $1000. IBM Selectric 71-3
I/O with TRS-80 print port interface, $650.
Will sell both for $1400. D. Bowie, Box
3453, San Francisco, CA 94119, 415-861-
6883.

For Sale: S. D. Expandoram, S-100, 16K
with 4115s, assembled, never used. $175 or
best offer. Call 701-968-4525, or write T.
Cartwright, Box 301, Cando, ND 58324.

Sarasota, FL

Dynabyte computer systems, Hazeltine and
NEC, Word Star, Structured Systems account-
ing. Consulting, training, sales, service.

Glisco, Inc., 4001 Roberts Point Rd., Sarasota,
FL 33581, .349-0200.

Aurora, IL

Microcomputer systems for home or
business; peripherals, software, books &
magazines Apple, Hewlett-Packard, North
Star, Cromemco systems. IDS-440G printer
w/Apple graphics. New HP-85 & HP calcula-
tors Farnsworth Computer Center, 1891 N.
Farnsworth Ave., Aurora, IL 60505, 851-3888.

Chicago, IL

Brand new lowest prices, never undersold,
postpaid in USA — Teletype 43 keyboard
printers, Okidata & Integral Data printers,
SS-50 bus computers, peripherals & business
software. Data Mart, 914 East Waverly Street,
Arlington Heights, IL 60004, 390-8525.

Garden City, Ml

Complete systems for business, professional
and personal applications. Custom program-
ming available. Apple II, North Star, Vector
Graphic and other lines of microcomputers,
software, books, components. Computer
Center, 28251 Ford Rd., Garden City, Ml
48135, 422-2570.

For Sale: Back issues of Byte, all my begin-
ning computer books and cassette learning
tapes, assorted electronic books, etc. Send
SASE for list to Don Hastings, Box 366,
Hemingway, SC 29554.

For Sale: Heath H8 w/16K, H8-5. H9 w/
GRAFIX and page erase. Heath cassette re-
corder, software, complete documentation.
Complete system, up and running, $650.
Dave Leupp, 852 Westover Terr., Whiteman
AFB, MO 65305, 816-563-2208.

For Sale: TRS-80, Level II, 16K w/ many ex-
tras, $600. Mint condition. Kilobaud issues
#1 to present. Best offer. Larry Guerrera,
Box 933, Woodside, NY 11377, 212-545-
4917.

For Sale: Eaton LRC 7000+ 64 char, print-
er, $250. Radio Shack Quick Printer II, 32
char. (Cat. No. 26-1155), $150. Send certi-
fied check or money order: Wm. R. Spencer,
Jr., 5421 Grandin Rd. Ext., Salem, VA
24153.

Wanted: 610 expansion board for OSI C1P.
With or without RAM chips. Send price and
description to Gary Rinehart, RR#3, North
Manchester, IN 46962.

Westland, Ml

Integrated circuits, TTL, CMOS, linear Many
hard to find "S" and "LS" types. Resistors,
capacitors, diodes, 1C sockets and many other
items Westland Electronics, 34245 Ford Rd.,
Westland, Ml 48185, 728-0650.

Hannibal, MO

Ohio Scientific products, modifications, ser-
vice, software 8" disk for Clp, C4p Process
control specialist E&l Technical Service, 5300
Paris Gravel Road, Hannibal, MO 63401, 248-
0084.

St. Louis, MO

Experimenters' Paradise. Electronic and
mechanical components Computer People,
Audio People, Hams, Robot Builders, Experi-
menters Open six days a week Gateway Elec-
tronics Corp., 8123-25 Page Blvd., St. Louis,
MO 63130, 427-6116.

Portland, OR

Ohio Scientific specialists for business and
personal computers. Local service. Terminals,
printers, custom programming. Full OSI prod-
uct line on display! 10 AM to 6 PM M-F Fial
Computer, 11266 SE 21st Ave., Milwaukie, OR
97222, 654-9574.

For Sale— SWTP MP-16, 16K memory
board, excellent condition. Paid over $450.
Will sell for $299 or make offer. Call 702-
453-4775 after 5 pm.

For Sale: SWTP 6800 w/ 32K, SSB dual disk
drive, CT-64 & VM-64, Percom cassette in-
terface, manual and software and extra serial
and parallel cards. $3350. Will separate.
John Rogers, 312-549-0008 after 5 pm.

For Sale: Unused Polymorphic System 8813
with 32K RAM memory with floppy-disk
drives, printer interface and Abern-Sopher
Multiwriter III. System has Canadian import
tax paid. Offers for complete system to:
Bishop Management, #8—825 McBride
Blvd., New Westminster, B.C., Canada,
V3L 5B5. 604-525-8148.

For Sale: MSI-6800 microcomputer with
16K + RAM, 8K PROM board, two serial
ports, two cassette ports (J.P.C.), new Per-
com 5” disk with controller card, lots of disk
software. This system has been used very lit-
tle, $1700. KIM-1 with enclosure and all
manuals, $110. Mcca-Bcta high-speed cas-
sette recorder, 9600 baud, RS-232, $325.
Micon 32 char, terminal, 300 baud, RS-232,
$325. Everything for $2300 and you ship.
Bill Pinkerton, 129-2nd Ave., Indialantic,
FL 32903. 305-725-7016.

PET 2nd cassette ($60) + more PET equip.
Lots of software + manuals. For sale
(cheap!) or trade. Send SASE to D. Coles,
3713 Bay To Bay, Tampa, FL 33609.

Wanted: OSI b&w video board #540. If you
upgraded to color you have one gathering
dust. Mike Schroeder, 1251 Minnesota Ave.,
Detroit Lakes, MN 56501.

Sell: Heath system complete and assembled
H8, H9, 40K memory, H17 disk, 2 drives,
DEC writer, 2 cassette recorders. All pro-
grams documentation and disks. Only
$3500. Every item below kit price. E. Mc-
Cormick, 8 Monmouth Shire Lane, Spring
Lake, NJ 07762. 201^49-4093 after 7:00pm.

We support Level II and Model II. Books,
magazines, programs, parts, accessories,
peripherals, free literature, free seminars,
cassettes, floppies, filters, transformers, caps,
chips, CRTs Artco Electronics, 302 Wyoming
Ave., Kingston, PA 18704, 287-1014.

Sara, Mexico

Learn how to utilize and program the Z-80
microprocessor to maintain your company's
records in top shape This technique has just
been introduced to Mexico. Courses, applica-
tions, maintenance, service Digitales, S.A. de
C.V. Sara 4612, Mexico 14, D.F., 5-17-41-59.

MICRO

QUIZ

from page 19

Answer: 3
J = 1 => X(7) = 1
J = 2 => X(l) = 2
J = 3 => X(7) = 3
J =4 => X(2) = 4
J = 5 => X(2) = 5
J = 6 => X(l) = 6

(The next quiz question tests
your knowledge of digital elec-
tronics.)

For Sale: Xitan Z-80 system. Mainframe,
ZPU, SMB, VDB, 48K RAM, 16R ROM
(12K BASIC in ROM), keyboard, manuals,
software. Complete system $1800. Terry
Young, 4 Aiken St., Derry, NH 03038,
603-434-0257.

Wanted: Synertek KTM-2 keyboard and/or
Trendcom 200 printer. In return I will
fabricate an equal value of prototype PC
boards. R. Hegel, 7332 Portland Ave., Rich-
field, MN 55423.

TRS-80 Quick Printer-II plus nine rolls
paper and cables for keyboard and expan-
sion interface, $180. Like new, list over
$240. G. Atkinson, Box 40387, San Fran-
cisco, CA 94140, 415-647-9122.

Diablo Hytype 1 Model 1200. Best of the
“daisy wheel” printers. Brand new units
w/pin feed friction platen & print wheel. In-
terface for Apple, TRS-80 & CP/M systems,
maintenance manual and additional inter-
face info available. There is no better buy
anywhere. After 6 PM. Scott Priester, 211
White Water Ct., Greer, SC 29651 , 803-268-
0678.

CLAfllFIEDS

Classified advertisements are intended for use by persons desiring to buy, sell or
trade used computer equipment. No commercial ads are accepted.

Two sizes of ads are available. The $5 box allows up to 5 lines of about 35 charac-
ters per line, including spaces and punctuation. The $10 box allows up to 10 lines.
Minimize use of capital letters to save space. No special layouts allowed. Payment is
required in advance with ad copy. We cannot bill or accept credit.

Advertising text and payment must reach us 60 days in advance of publication
(i.e., copy for March issue, mailed in February, must be here by Jan. 1). The publisher
reserves the right to refuse questionable or inapplicable advertisements. Mail copy
with payment to: Classifieds, Kilobaud Microcomputing, Peterborough NH 03458
Do not include any other material with your ad as it may be delayed.

214 Microcomputing, October 1980

attention
Dealers

Make
Money. . .
Sell

kilobaud

MICROCOMPUTING

T.M.

Selling Kilobaud MICROCOMPUTING, the most
complete journal of microcomputing, brings the
computer enthusiast through your door. Once he’s
in your store, you can sell him anything.

For information on selling Kilobaud MICROCOM
PUTING, call 603-924-7296 and speak with Ginnie
Boudrieau, our bulk sales manager, or write to her
at Kilobaud Microcomputing, 80 Pine Street, Peter-
borough, NH 03458.

Our dealers are telling us that Kilobaud MICRO
COMPUTING is the hottest-selling computer
magazine on the newsstand, so call today and join
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★ Payment: Money Order. Cashier's Check, Certified Check Personal Checks require 3 weeks to clear
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★ Prices subject to change at any time.

★ Delivery of merchandise is subject to availability

★ UPS prepaid insured delivery: $1-5100. $5; $101-$500, $7. $501 up. 1.5% of order Model II must be
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if Texas Residents 915-597-0673

TCS, 106 East 10th. Brady, TX 76825. 800-351-1473

■‘ —wi smirk*

IN STOCK FOR IMMEDIATE SHIPMENT

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41 16 s 6 MONTH WARRANTY INSTRUCTIONS INCLUDED |

DISK DRIVES

PERCOM TFD-1 OO $325
PERCOM TFD- 200 $595
CCI-lOO $305
CCI-200 $495

2 DRIVE CABLE S24.95 4 DRIVE CABLE $34.95

PRINTERS $695

MICROTEK MT80P BI-DIRECTIONAL
1 25 CPS UPPER & LOWER CASE

1 YEAR WARRANTY

CABLE — $24.95

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v* Reader Service index— page 241

Microcomputing, October 1980 215

kb microcomputing book nook

MICRCK30MPUTING

• 40 COMPUTER GAMES— BK7381 — Forty games in all in nine
different categories. Games for large and small systems, and
even a section on calculator games. Many versions of BASIC
used and a wide variety of systems represented. A must for the
serious computer gamesman. $7.95*

• UNDERSTANDING AND PROGRAMMING MICROCOMPUTERS -BK7382-A valuable
addition to your computing library. This two part text includes the best articles that have ap-
peared in 73 and Kilobaud Microcomputing magazines on the hardware and software
aspects of the new microcomputing hobby. Well known authors and well structured text
helps the reader get involved in America’s fastest growing hobby. $10.95*

INTRODUCTORY

• HOBBY COMPUTERS ARE HERE! — BK7322— If you (or a friend) want to
come up to speed on how computers work . . . hardware and software . . .
this is an excellent book. It starts with the fundamentals and explains the
circuits, and the basics of programming. This book has the highest recom-
mendations as a teaching aid for newcomers. $4.95.*

• THE NEW HOBBY COMPUTERS— BK7340— This book takes it from
where “HOBBY COMPUTERS ARE HERE!” leaves off, with chapters on
Large Scale Integration, how to choose a microprocessor chip, an introduc-
tion to programming, low cost I/O for a computer, computer arithmetic,
checking memory boards . . . and much, much more! Don’t miss this tremen-
dous value! Only $4.95.*

INTRODUCTION TO MICROCOMPUTERS (VOL 0-///)

• AN INTRODUCTION TO MICROCOMPUTERS, VOL. 0-

BK1 130 — The Beginner’s Book- Written for readers who know
nothing about computers -for those who have an interest in
how to use computers — and for everyone else who must live
with computers and should know a little about them. The first in
a series of 4 volumes, this book will explain how computers
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tegral part of life and society. During any given day you are af-
fected by computers, so start learning more about them with
Volume 0. $7.95.*

Mkt<X° ,n P atc '

Tools

Techniques

Electronics

• VOL. I - BK1030-2nd Edition completely revised. Dedicated
to the basic concepts of microcomputers and hardware theory.
The purpose of Volume I is to give you a thorough understand-
ing of what microcomputers are. From basic concepts (which
are covered in detail), Volume I builds the necessary compo-
nents of a microcomputer system. This book highlights the dif-
ference between minicomputers and microcomputers. $12.50.*

• VOL. II — BK1040 (with binder) — $30.00* —Contains descrip-
tions of individual microprocessors and support devices used
only with the parent microprocessor. Volume II describes all
available chips.

• VOL. Ill — BK1 133 (with binder) -$20.00.* Contains descrip-
tions of all support devices that can be used with any micropro-
cessor.

• HOW TO BUILD A MICROCOMPUTER - AND REALLY UNDERSTAND IT- BK7325 - by
I Sam Creason. The electronics hobbyist who wants to build his own microcomputer

system now has a practical “How-To” guidebook. This book is a combination technical
' manual and programming guide that takes the hobbyist step-by-step through the design,
construction, testing and debugging of a complete microcomputer system. Must reading
for anyone desiring a true understanding of small computer systems. $9.95.*

• TOOLS & TECHNIQUES FOR ELECTRONICS- BK7348- by A. A. Wicks is an easy-to-
understand book written for the beginning kit builder as well as the experienced hob-
byist. It has numerous pictures and descriptions of the safe and correct ways to use
basic and specialized tools for electronic projects as well as specialized metal working
tools and the chemical aids which are used in repair shops. $4.95.*

"Use the order card in the back ot this magazine or itemize your order on a separate piece of paper and mail to Kilobaud Microcomputing Book
Department • Peterborough NH 03458. Be sure to include check or detailed credit card information. No C.O.D. orders accepted. All orders add $1.00
handling. Please allow 4-6 weeks for delivery. Questions regarding your order? Please write to Customer Service at the above address.

FOR TOLL FREE ORDERING CALL 1-800-258-5473

kb microcomputing book nook

FOR TOLL FREE ORDERING CALL 1-800-258-5473

SPECIAL INTERESTS

• TRS-80 DISK AND OTHER MYSTERIES- BK1181 - by Har-
vard C. Pennington. This is the definitive work on the TRS-80
disk system. It is full of detailed “How to” information with ex-
amples, samples and in-depth explanations suitable for begin-
ners and professionals alike. The recovery of one lost file is
worth the price alone. $22.50.*

• INTRODUCTION TO TRS-80 GRAPHICS- BK1180- by Don
Inman. Dissatisfied with your Level I or Level II manual’s
coverage of graphics capabilities? This well-structured book
(suitable for classroom use) is ideal for those who want to use
all the graphics capabilities built into the TRS-80. A tutorial
method is used with many demonstrations. It is based on the
Level I, but all material is suitable for Level II use. $8.95.*

• MICROPROCESSOR INTERFACING TECHNIQUES- BK1037
-by Austin Lesea & Rodnay Zaks will teach you how to inter-
connect a complete system and interface it to all the usual
peripherals. It covers hardware and software skills and tech-
niques, including the use and design of model buses such as
the IEEE 488 orSIOO. $15.95.*

• MICROPROCESSOR LEXICON -ACRONYMS AND DEFINITIONS- BK1137-Compiled by the staff of SYBEX is a convenient
reference in pocket size format. Sections include acronyms and definitions, part numbers and their definitions, S-100 signals,
RS232 signals, IEEE 499 signals, microcomputer and microprocessors, JETDS summary (military) and a code conversion table.
$2.95.*

• MICROPROCESSORS FROM CHIPS TO SYSTEMS - BK1036 — by Rodnay Zaks is a complete and detailed introduction to
microprocessors and microcomputer systems. No preliminary knowledge of computers or microprocessors is required to read
this book, although a basic engineering knowledge is naturally an advantage. Intended for all wishing to understand the con-
cepts, techniques and components of microprocessors in a short time. $10.95.*

MONEYMAKING

• HOW TO MAKE MONEY WITH COMPUTERS - BK1003- In
10 information-packed chapters, Jerry Felsen describes more
than 30 computer-related, money-making, high profit, low
capital investment opportunities. $15.00.*

• HOW TO SELL ANYTHING TO ANYBODY - BK7306 - Ac-
cording to The Guinness Book of World Records, the author,
Joe Girard, is “the world’s greatest salesman.” This book
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• FREELANCE SOFTWARE PUBLISHING - BK1 179- by B. J.
Korites. “This book is about money and how to make it by
writing and selling computer programs,” (author’s foreword). If
you have the skills to write a saleable program, you now need to
acquire the skills to sell that program. This compact book com-
prehensively covers the entire publishing process and many
aspects of software salesmanship. $14.95.*

• THE INCREDIBLE SECRET MONEY MACHINE- BK1 178-by Don Lancaster. A dif-
ferent kind of “cookbook” from Don Lancaster. Want to slash taxes? Get free vacations?
Win at investments? Make money from something that you like to do? You’ll find this
book essential to give you the key insider details of what is really involved in starting up
your own money machine. $5.95.*

BUSINESS

*Use the order card in the back of this magazine or itemize your order on a separate piece of paper and mail to Kilobaud Microcomputing Book
Department • Peterborough NH 03458. Be sure to include check or detailed credit card information. No C.O.D. orders accepted. All orders add $1.00
handling. Please allow 4-6 weeks for delivery. Questions regarding your order? Please write to Customer Service at the above address.

• PAYROLL WITH COST ACCOUNTING - IN BASIC- BK1001 - by L. Poole & M.
Borchers, induces program listings with remarks, descriptions, discussions of
the principle behind each program, file layouts, and a complete user’s manual with
step-by-step instructions, flowcharts, and simple reports and CRT displays. Pay-
roll and cost accounting features include separate payrolls for up to 10 com-
panies, time-tested interactive data entry, easy correction of data entry errors, job
costing (labor of distribution), check printing with full deduction and pay detail,
and 16 different printed reports, including W-2 and 941 (in CBASIC). $20.00.*

• SOME COMMON BASIC PROGRAMS— BK1053— published by Adam Osborne &
Associates, Inc. Perfect for non-technical computerists requiring ready-to-use pro-
grams. Business programs, plus miscellaneous programs. Invaluable for the user
who is not an experienced programmer. All will operate in the stand-alone mode.
$12.50 paperback.*

• PIMS: PERSONAL INFORMATION MANAGEMENT SYSTEM - BK1009- Learn
how to unleash the power of a personal computer for your own benefit in this
ready-to-use data-base management program. $11.95.*

PROGRAMMING & COOK BOOKS

CMOS

COOKBOm

8080 / 8080A

kb microcomputing book nook

-Z80-

e >rA

V** INSIDE LEVEL II — BK1 183 — For machine language program-
mers! This is a comprehensive reference guide to the Level "
ROMs, allowing easy utilization of the sophisticated routines
they contain. It concisely explains set-ups, calling sequences,
variable passage and I/O routines. Part II presents an entirely
new composite program structure which unloads under the
SYSTEM command and executes in both BASIC and machine
code with the speed and efficiency of a compiler. Special con-
sideration is given to disk systems. $15.95.*

• PROGRAMMING THE Z-80 - BK1 122 - by Rodnay Zaks. Here
is assembly language programming for the Z-80 presented as a
progressive, step-by-step course. This book is both an educa-
tional text and a self-contained reference book, useful to both
the beginning and the experienced programmer who wish to
learn about the Z-80. Exercises to test the reader are included.
$14.95.*

• Z-80 ASSEMBLY LANGUAGE PROGRAMMING - BK1 1 77 -

by Lance A. Leventhal. This book thoroughly covers the Z80 in-
struction set, abounding in simple programming examples
which illustrate software development concepts and actual
assembly language usage. Features include Z80 I/O devices
and interfacing methods, assembler conventions, and compari-
sons with 8080A/8085 instruction sets and interrupt structure.
$12.50.*

• Z-80 SOFTWARE GOURMET GUIDE AND COOKBOOK-

BK1045 — by Nat Wadsworth. Scelbi’s newest cookbook! This
book contains a complete description of the powerful Z-80 in-
struction set and a wide variety of programming information.
Use the author’s ingredients including routines, subroutines
and short programs, choose a time-tested recipe and start
cooking! $15.95.*

-6502-

• PROGRAMMING THE 6502 (Second Edition)- BK1005-
Rodnay Zaks has designed a self-contained text to learn pro-
gramming, using the 6502. It can be used by a person who has
never programmed before, and should be of value to anyone us-
ing the 6502. The many exercises will allow you to test yourself
and practice the concepts presented. $12.95.*

• 6502 APPLICATIONS BOOK - BK1006 - Rodnay Zaks
presents practical-application techniques for the 6502 micro-
processor, assuming an elementary knowledge of
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own domestic-use systems and peripherals. Self-test exercises
included. $12.95.*

• 6502 ASSEMBLY LANGUAGE PROGRAMMING - BK1 176 —

by Lance A. Leventhal. This book provides comprehensive
coverage of the 6502 microprocessor assembly language.
Leventhal covers over 80 programming examples from simple
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clude 6502 assembler conventions, input/output devices and in-
terfacing methods, and programming the 6502 interrupt
system. $12.50.*

• 6502 SOFTWARE GOURMET GUIDE AND COOKBOOK -

BK1055-by Robert Findley. This book introduces the BASIC
language programmer into the realm of machine-language pro-
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gredients in this cookbook. “Recipes” are included to help you
put together exactly the programs to suit your taste. $12.95.*

• 8080A/8085 Assembly Language Programming— by Lance
Leventhal— BK1004— Assembly language programming for the
8080A/8085 is explained with a description of the functions of as-
semblers and assembly instructions, and a discussion of basic
software development concepts. Many fully debugged, practical
programs are included as is a special section on structured pro-
gramming. $12.50.*

• 8080 PROGRAMMING FOR LOGIC DESIGN-BK1078-ldeal

reference for an indepth understanding of the 8080 processor.
Application-oriented and the 8080 is discussed in light of replac-
ing conventional, hard-wired logic. Practical design considera-
tions are provided for the implementation of an 8080-base con-
trol system. $9.50.*

• 8080 SOFTWARE GOURMET GUIDE AND COOKBOOK-

BK1102 — If yu have been spending too much time developing
simple routines for your 8080, try this new book by Scelbi Com-
puting and Robert Findley. Describes sorting, searching, and
many other routines for the 8080 user. $12.95.*

-6800-

• 6800 PROGRAMMING FOR LOGIC DESIGN— BK1077— Ori-
ented toward the industrial user, this book describes the process
by which conventional logic can be replaced by a 6800
microprocessor. Provides practical information that allows an
experimenter to design a complete micro control system from
the “ground up.” $9.50.*

• 6800 SOFTWARE GOURMET GUIDE AND COOKBOOK-

BK1075-Like its culinary cousin, The 8080 Gourmet Guide,
this book by Scelbi Computing and Robert Findley describes
sorting, searching and other routines — this time for the 6800
user. $12.95.*

COOK BOOKS-

• CMOS COOKBOOK- BK1011 —by Don Lancaster. Details
the application of CMOS, the low power logic family suitable
for most applications presently dominated by TTL. Required
reading for every serious digital experimenter! $10.50.*

• TVT COOKBOOK — BK1064 — by Don Lancaster. Describes
the use of a standard television receiver as a microprocessor
CRT terminal. Explains and describes character generation,
cursor control and interface information in typical, easy-to-
understand Lancaster style. $9.95.*

• TTL COOKBOOK- BK1063 — by Donald Lancaster. Explains
what TTL is, how it works, and how to use it. Discusses prac-
tical applications, such as a digital counter and display
system, events counter, electronic stopwatch, digital voltmeter
and a digital tachometer. $9.50.*

• MICROCOMPUTING CODING SHEETS Microcomputing's

dozen or so programmers wouldn’t try to work without these
handy scratch pads, which help prevent the little errors that can
cost hours and hours of programming time. Available for
programming is Assembly/Machine Language (PD1001), which
has columns for address, instruction (3 bytes), source code
(label, op code, operand) and comments; and for BASIC
(PD1002) which is 72 columns wide. 50 sheets to a pad. $2.39.*

*Use the order card in the back of this magazine or itemize your order on a separate piece of paper and mail to Kilobaud Microcomputing Book
Department • Peterborough NH 03458. Be sure to include check or detailed credit card information. No C.O.D. orders accepted. All orders add $1.00
handling. Please allow 4-6 weeks for delivery. Questions regarding your order? Please write to Customer Service at the above address.

FOR TOLL FREE ORDERING CALL 1-800-258-5473

kb microcomputing book nook

BASIC AND PASCAL

NEW REVISED EDITION

• PROGRAMMING IN PASCAL— BK1 140— by Peter Grogono. The computer
programming language PASCAL was the first language to embody in a
coherent way the concepts of structured programming, which has been
defined by Edsger Dijkstra and C.A.R. Hoare. As such, it is a landmark in the
development of programming languages. PASCAL was developed by
Niklaus Wirth in Zurich; it is derived from the language ALGOL 60 but is
more powerful and easier to use. PASCAL is now widely accepted as a
useful language that can be efficiently implemented, and as an excellent
teaching tool. It does not assume knowledge of any other programming
language; it is therefore suitable for an introductory course. $12.95/

• THE BASIC HANDBOOK— BK1 174— by David Lien. This book
is unique. It is a virtual ENCYCLOPEDIA of BASIC. While not
favoring one computer over another, it explains over 250 BASIC
words, how to use them and alternate strategies. If a computer
does not possess the capabilities of a needed or specified
word, there are often ways to accomplish the same function by
using another word or combination of words. That’s where the
HANDBOOK comes in. It helps you get the most from your com-
puter, be it a “bottom-of-the-line” micro or an oversized
monster. $14.95.*

• LEARNING LEVEL II — BK1 175 — by David Lien. Written
especially for the TRS-80, this book concentrates on Level II
BASIC, exploring every important BASIC language capability.
Updates are included for those who have studied the Level I
User’s Manual. Sections include: how to use the Editor, dual
cassette operation, printers and peripheral devices, and the
conversion of Level I programs to Level II. $15.95.*

• BASIC NEW 2ND EDITION - BK1081 - by Bob Albrecht. Self-teaching guide to
the computer language you will need to know for use with your microcomputer.
This is one of the easiest ways to learn computer programming. $6.95.*

• BASIC BASIC (2ND EDITION)- BK1026- by James S. Coan.

This is a textbook which incorporates the learning of computer
programming using the BASIC language with the teaching of
mathematics. Over 100 sample programs illustrate the tech-
niques of the BASIC language and every section is followed by
practical problems. This second edition covers character string
handling and the use of data files. $9.45.*

• ADVANCED BASIC - BK1000 - Applications, including
strings and files, coordinate geometry, area, sequences and
series, simulation, graphing and games. $9.65*.

• MY COMPUTER LIKES ME. . .WHEN I SPEAK BASIC- BK1039- An introduction to BASIC
. . . simple enough for kids. If you want to teach BASIC to anyone quickly, this is the way to go.

$3.95.*

• SIXTY CHALLENGING PROBLEMS WITH BASIC SOLUTIONS (2nd Edition)- BK1073- by Donald
Spencer, provides the serious student of BASIC programming with interesting problems and solu-
tions. No knowledge of math above algebra required. Includes a number of game programs, as well as
programs for financial interest, conversions and numeric manipulations. $6.95.*

games:

• WHAT TO DO AFTER YOU HIT RETURN - BK1071 - PCC’s
first book of computer games ... 48 different computer games
you can play in BASIC . . . programs, descriptions, many illus-
trations. Lunar Landing, Hammurabi, King, Civel 2, Qubic 5,
Taxman, Star Trek, Crash, Market, etc. $10.95.*

• BASIC COMPUTER GAMES- BK1074-Okay, so once you
get your computer and are running in BASIC, then what? Then
you need some programs in BASIC, that’s what. This book has
101 games for you from very simple to real buggers. You get the
games, a description of the games, the listing to put in your
computer and a sample run to show you how they work. Fun.
Any one game will be worth more than the price of the book for
the fun you and your family will have with it. $7.50.*

• MORE BASIC COMPUTER GAMES- BK1 182 -edited by
\ David H. Ahl. More fun in BASIC! 84 new games from the people

•A \who brought you BASIC Computer Games. Includes such
favorites as Minotaur (battle the mythical beast) and Eliza
(unload your troubles on the doctor at bargain rates). Complete
with game description, listing and sample run. $7.50.*

•Use the order card in the back of this magazine or itemize your order on a separate piece of paper and mail to Kilobaud Microcomputing Book Department
• Peterborough NH 03458. Be sure to include check or detailed credit card information. No C.O.D. orders accepted. All orders add $1.00 handling.
Please allow 4-6 weeks for delivery. Questions regarding your order? Please write to Customer Service at the above address.

FOR TOLL FREE ORDERING CALL 1-800-258-5473

Comes with Backgam-
mon and Tic-Tac-Toe on
tape with full documen-
tation and program list-
ing. Requires 9v. battery.
Part No. IBEX $19.95

APPLE II HOBBY/
PROTOTYPING CARD

Part No. 7907 $1 4.95

APPLE II
PARALLEL
INTERFACE

Interfaces printers, syn-
thesizers keyboards, and
JBE A-D D-A Converter
& Switches. This inter-
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with handshaking logic,
2-6522 VIA’s and a
74LS74 for timing. In-
puts and outputs are
TTL compatible. Part
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Kit— $69.95 • Part No.
79295A Assembled—
$79.95

REALTIME
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transaction printouts,
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battery backup.
MHPX004— $349.00

16K EPROM

Uses 2708 EPROMS,

memory speed selec-
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65K of memory, can
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EPROMs $49. 95 part
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PET COMPUTER

With 1 6K &. monitor—
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OPTO-ISOLATED
PARALLEL INPUT
BOARD FOR
APPLE II

There are 8 inputs that
can be driven from
TTL logic or any 5 volt
source. The circuit
board can be plugged
into any of the 8 sockets
of your Apple II. It has
a 16 pin socket for
standard dip ribbon
cable connection.
Board only$1 5.00. Part
No. 120, with parts
$69.95. Part No. 120A.

VIDEO TERMINAL

1 6 lines, 64 columns •
Upper and lower case

• 5x7 dot matrix • Se-
rial RS-232 in and out
with TTL parallel
keyboard input • On
board baud rate
generator 75, 110,
150, 300, 600, &
1200 jumper select-
able • Memory 1024
characters (7-21 L02)

• Video processor chip
SFF96364 by Necu-
lonic • Control char-
acters (CR, LF,

t, 1, non destructive
cursor, CS, home, CL

• White characters on
black background or
vice-versa • With the
addition of a key-
board, video monitor
or TV set with TV
interface (part no.
107A) and power
supply this is a com-
plete stand alone
terminal • also S-100
compatible • requires
+ 16, & -16 VDC at
100mA, and 8VDC at
1 A. Part No. 1000A
$199.95 kit.

PARALLEL
TRIAC OUTPUT
BOARD FOR
APPLE II

This board has 8 triacs capable of switching
110 volt 8 amp loads (660 watts per channel) or a
total of 5280 watts. Board only $1 5.00 Part No.
210, with parts $1 1 9.95 Part No. 21 OA

APPLE lltt
SERIAL I/O |

INTERFACE 1

Baud rate is continuously adjustable from 0
to 30,000 • Plugs into any peripheral
connector • Low current drain. RS-232 input
and output • On board switch selectable 5 to
8 data bits, 1 or 2 stop bits, and parity or no
parity either odd or even • Jumper selectable
address • SOFTWARE • Input and Output
routine from monitor or BASIC to teletype or
other serial printer • Program for using an
Apple II for a video or an intelligent terminal.
Also can output in correspondence code to
interface with some selectrics. • Also
watches DTR • Board only $1 5.00 Part No.
2, with parts $42.00 Part No. 2A, assembled
$62.00 Part No. 2C

8K EPROM PICEON

• Programs 2708’s address relocation of each
4K of memory to any 4K boundary • Power on
jump and reset jump option for "turnkey”
systems and computers without a front panel

• Program saver software in 1 2708 EPROM
$25. Bare board $35 including custom coil,
board with parts but no EPROMS $1 39. with 4
EPROMS $1 79, with 8 EPROMS $219.

SPINWRITER
MODELS 5510 and 5520

Features— EIA RS-232C/CCITT V.24 Inter-
face Standard • 55 Characters Per Second
Maximum Print Rate • Impeccable Print Quality
(OCR Quality) • Microprocessor Electronics •
High Resolution Plotting/Graphing • Lowest
Operating Noise Level • Self-Test Printing •
Operator Engineered Control Panel • Prints
Original and up to Seven Copies • NEC Informa-
tion Systems new Model 5510 Receive Only and
Model 5520 Keyboard Send/Receive SPIN-
WRITER terminals are microprocessor con-
trolled serial, impact terminals designed for
remote printing applications where impeccable
print quality is required. Model 5510 RO, Part
No. NECA30759 $2795.95 • Model 5520
KSR, Part No. NECA30762 $3095.95

D.C. HAYES MICROMODEM

Fully S-100 bus compatible including 16-bit
machines and 4 MHz processors. • Two soft-
ware selectable Baud rates— 300 Baud and a
jumper selectable speed from 45 to 300 Baud.
(110 standard). Supports originate and answer
modes. • Direct-connect Microcoupler. This
FCC-registered device provides direct access
into your local telephone system, with none of
the losses or distortions associated with acous-
tic couplers and without a telephone company
supplied data access arrangement. • Auto-
Answer/Auto-Call. The MICROMODEM 100
can automatically answer the phone and receive
input; it can also dial a number automatically. •
Automatic Reset and Disconnect. • Software
compatible with the D.C. Hayes Associates
80-1 03 A Data Communications Adapter.
Micromodem-DCHA32625— $379.95

TIDMA

Tape Interface Direct Memory Access • Record
and play programs without bootstrap loader (no
prom) has FSK encoder/decoder for direct con-
nections to low cost recorder at 1 200 baud rate,
and direct connections for inputs and outputs to
a digital recorder at any baud rate • S-100 bus
compatible • Board only $35.00 Part No. 112,
with parts $110.00 Part No. 112A.

SYSTEM MONITOR

8080, 8085, or Z-80 System monitor for use
with the TIDMA board. There is no need for
the front panel. Complete with documentation
$12.95.

RS-232/TTY

SERIAL I/O

This board has two
active circuits, one con-
verts RS-232 to 20 mA,
the other converts 20
mA to RS-232. Re-
quires +12 and -12
volts. $9.95 Part No.
600A Kit.

Four Serial I/O RS-232
ports. S-100 Bus, Soft-
ware or jumper selectable
baud rate (1 10, 300, 600,
1200,2400,4800,9600,
19.2K), on board Xtal baud
rate generator, Address-
ing, switch selectable.
Parity or no parity (odd or
even) switch selectable, 1
or 2 stop bits, 5 to 8
bits/character. Board only
$29.95, Part No. 7908.
With parts (kit) $199.95,
Part No. 7908A.

S-100 BUS
ACTIVE TERMINATOR

Board only $14.95 Part No. 900, with parts
$24.95 Part No. 900A

Send for FREE Catalog.. .a big self addressed envelope with 80<£ postage gets it fastest!

Tn f|rHpr- Mention part no., description, and price. In USA shipping paid by us for orders accompanied by check or money
lu UI uci . order. We accept C.O.D. orders (U.S. only) or a VISA or Master Charge no., expiration date, signature and phone
no., shipping charges will be added. CA residents add 6.5°/o for tax. Outside USA add 1 5°/o for air mail postage
and handling. Payment must be in U.S. dollars. Dealer inquiries invited. Prices subject to change without notice.

Order Line: (408) 448-0800

ELECTRONIC SYSTEMS Dept.KB,P.O. Box 21638, San Jose, CA USA 95151

220 Microcomputing, October 1980

HEX ENCODED KEYBOARD

Four onboard LEDs indi-
cate the HEX code gen-
erated for each key
depression. The board
requires a single +5
volt supply. Board only
$15.00 Part No. HEX-3,
with parts $49.95 Part
No. HEX- 3A. 44 pin
edge connector $4.00
Part No. 44 P.

T.V.

TYPEWRITER

• Stand alone TVT

• 32 char/line, 16
lines, modifications for
64 char/line included

• Parallel ASCII (TTL)
input • Video output

• 1 K on board memory

• Output for computer
controlled curser •
Auto scroll • Non-
destructive curser •
Curser inputs: up, down,
left, right, home, EQL,
EOS • Scroll up, down

• Requires +5 volts
at 1.5 amps, and -1 2
volts at 30 mA • All
7400, TTL chips •
Char. gen. 2513 •
Upper case only •
Board only $39.00
Part No. 106, with
parts $145.00 Part
No. 1 06A

44 BUS MOTHER
BOARD

Has provisions for ten
44 pin (.156) connec-
tors, spaced 3/4 of an
inch apart. Pin 20 is
connected to X, and
22 is connected to Z
for power and ground.
All the other pins are
connected in parallel.
This board also has
provisions for bypass
capacitors. Board
cost $15.00 Part No.
102. Connectors
$3.00 each Part No.
44WP.

UART &
BAUD RATE
GENERATOR

• Converts serial to
parallel and parallel to
serial • Low cost on
board baud rate gener-
ator • Baud rates:
110, 150, 300, 600,
1200, and 2400 •
Low power drain +5
volts and -12 volts
required • TTL com-
patible • All characters
contain a start bit. 5
to 8 data bits, 1 or 2
stop bits, and either
odd or even parity. • All
connections go to a 44
pin gold plated edge
connector • Board only
$12.00 Part No. 101,
with parts $35.00 Part
No. 101 A. 44 pin edge
connector $4.00 Part
No. 44P

RS-232/20mA

INTERFACE

This board has two
passive, opto-isola-
ted circuits. One con-
verts RS-232 to
20mA, the other con-
verts 20mA to RS-
232. All connections
go to a 10 pin edge
connector. Requires
+12 and -12 volts.
Board only $9.95,
part no. 7901, with
parts $14.95 Part
No. 7901A.

ASCII TO CORRESPONDENCE
CODE CONVERTER

This bidirectional board is a direct replace-
ment for the board inside the Trendata 1000
terminal. The on board connector provides
RS-232 serial in and out. Sold only as an
assembled and tested unit for $249.95.
Part No. TA100QC

ASCII KEYBOARD

53 Keys popular ASR-33 format • Rugged
G-10 P. C. Board • Tri-mode MOS encoding

• Two-Key Rollover • MOS/DTL/TTL Compat-
ible • Upper Case lockout • Data and Strobe
inversion option • Three User Definable
Keys • Low contact bounce • Selectable Par-
ity • Custom Keycaps • George Risk Model
753. Requires +5, -12 volts. $59.95 Kit.

ASCII KEYBOARD

TTL & DTL compatible • Full 67 key array

• Full 12B character ASCII output • Positive
logic with outputs resting low • Data Strobe

• Five user-definable spare keys • Standard
22 pin dual card edge connector • Requires
+5VDC, 325 mA. Assembled & Tested.
Cherry Pro Part No. P70-05AB. $119.95.

A-to-D D-to-A CONVERTER

Analog to Digital,
Digital to Analog
Converter, A-D con-
version time 20us.
D-A conversion
5us. Uses include
speech and music
synthesizing and
slow scan TV. Sin-
gle power supply (5V), 8 Bits wide, latched I/O,
strobe lines. Part No. 79287K Complete Kit
$49.95 • Part No. 79287A Assembled $69.95

SOLID STATE SWITCH

Your computer can control power
(120VAC) to your printer, lights,
and other 120VAC appliances up
to 720 watts (6AMPS at 1 20VAC1
Input 3 to 15 VDC, 2-13 MA TTL
compatible, isolation 1500V. Part No. 79000K
1 Channel Kit $9.95 • Assm. $1 2.50 • Part No.
79004K 4 Channel Kit $34.95 • Assm. $44.95.

SUPER MODEM

T.V. INTERFACE

• Converts video to
AM modulated RF.
Channels 2 or 3. So
powerful almost no
tuning is required. On
board regulated power
supply makes this ex-
tremely stable. Rated
very highly in Doctor
Dobbs' Journal. Recom-
mended by Apple •
Power required is 12
volts AC C.T., or +5
volts DC • Board only
$7.60 part No. 107,
with parts $1 3.50 Part
No. 1 07A

SOROC IQ 120

Upper/ lower case dis-
play • Numeric keypad
& cursor keys • Pro-
tected fields, Vs inten-
sity display • RS 232
interface & aux. port.
IQ120— $799.95 •
IQ140 Detachable key-
board— $1 1 99.95

RS-32/TTL

INTERFACE

TAPE

INTERFACE

• Converts a low cost
tape recorder to a
digital recorder • Works
up to 1 200 baud • Dig-
ital in and out are TTL-
serial • Output of
board connects to mic.
in of recorder • Ear-
phone of recorder con-
nects to input on board

• No coils • Requires
+5 volts, low power
drain • Board only
$7.60 Part No. Ill,
with parts $29. 95Part
No. 1 1 1 A

MODEM

• Type 1 03 • Full or half
duplex • Works up to
300 baud • Originate
or Answer# Serial TTL
input and output • con-
nect 8 O speaker and
crystal mic. directly to
board • Requires +5
volts • Board only $7.60
Part No. 1 09, with parts
$29.95 Part No. 109 A.

• Converts TTL to RS-
232, and converts RS-
232 to TTL • Two se-
parate circuits • Re-
quires -12 and +12
volts • All connections
go to a 10 pin edge
connector, kit $9.95 Part
Nq 232A1 OPin edge con-
nector $3.00 part No.
10P.

With reg. keyboard
MOD3 8K $1449.95
M0D4 16 K $1495.95
MOD5 32K $1699.95
Without disk drive sub-
tract $450.00. Add-on
drives. $495.00. With
101 key option add
$134.95. With 117 key
option add $1 79.95.

Orignate, RS-232 and
20 mA compatable, Full
duplex, and half duplex,
direct connect or a-
coustic coupled, on
board power supply, car-
rier detect light, DB25 plug , 300 BAUD, Type
1 03 compatable frequencies, Bare board Part
No. 2000, $19,95, Kit Part No. 2000A, $99.95.

DC POWER SUPPLY

• Board supplies a regulated +5
volts at 3 amps., +1 2, -1 2. and -5
volts at 1 amp. • Power required is
8 volts AC at 3 amps., and 24 volts
AC C.T. at 1.5 amps. • Board only
$12.50 Part No. 6085, with parts
excluding transformers $42.50
Part No. 6085A

W To Order:

Imm.

Send for FREE Catalog.. .a big self addressed envelope with 80<C postage gets it fastest!

TO Order* Mention part no., description, and price. In USA shipping paid by us for orders accompanied by check or money
iu ui uui - on j er yy e accep t C.O.D. orders (U.S. only) or a VISA or Master Charge no., expiration date, signature and phone
1 no., shipping charges will be added. CA residents add 6.5°/o for tax. Outside USA add 1 5°/o for air mail postage
and handling. Payment must be in U.S. dollars. Dealer inquiries invited. Prices subject to change without notice.

Order Line: (408) 448-0800 ^ 47

ELECTRONIC SYSTEMS Dept.KB,P.O. Box 21638, San Jose, CA USA 95151

iS Reader Service index— page 241

Microcomputing, October 1980 221

Terminals

CompuMart has been selling com-
puters by mail since 1971. Our thou-
sands of satisfied customers rely on
CompuMart for services not generally
available from the others. Namely:

• Product Selection/Each product ad-
vertised by CompuMart has been eval-
uated by our in-house staff for best
price, performance, and supplier reli-
ability

• Return Privilege/After receipt of our
products, you are protected by Compu
Mart’s exclusive, 10-day return privi-

ledge- good for all products except
software.

• Support/Our Customer Service Dept,
and axpert technicians are always there
to assist you by phone or at Compu-
Mart’s outlets. Our knowledgeable
phora sales force can provide you with
detailed information and complete
product specifications.

• Phone Ordering/For added conveni-
ence, CompuMart maintains a toll-free
ordering number. 1-800-343-5504.

Televideo 91 2C

820 x 24— Lower case descenders. Teletype or
telewriter keyboard. 110/220 VAC. 50 to 19.2K Baud
Item entry pad. Great looking and no fan
noise.

Televideo 920C

Similar to the TV 912 but has programmable
function keys across top.

Excellent for text editing.

Call for Introductory
Sale Prices

We’ve got the following Lear Sieg-
ler Terminals In Stock at prices
too low to print— Call for quotes.

ADM-3A Industries favorite dumb terminal for
some very smart reasons.

ADM-3A.+ New from Lear Siegler. CALL!

ADM-31. The terminal that’s too smart to be con-
sidered dumb.

ADM-42. Available with keyboard semi-
intelligent terminal offering tremendous user flexi-
bility. The optional configurations
are amazing.

Call for details.

with

lO day free return

HAZELTINE TERMINALS AT
SPECTACULAR SAVINGS!

Printers

The Paper Tiger
Printer From
Integral Data

Uses standard % inch roll
paper and ribbon
40 characters per line
Speed: 40 characters
per second
UL approved

737-3 (Serial Interface)

Hazeltine 1410.
Hazeltine 1420.
Hazeltine 1500.
Hazeltine 1510.
Hazeltine 1520.
Hazeltine 1552.

List $850 CompuMart $749

List $995 CompuMart $895

List $1095 CompuMart $995

List $1395 CompuMart $1325

List $1585 CompuMart $1485

List $1395 CompuMart $1295

Call CompuMart for complete specs
and quantity discounts.

Calculators

A CALCULATOR, A SYSTEM, A
WHOLE NEW STANDARD.

High resolution dot
matrix impact printer

IDS Paper Tiger Printer $995

IDS Graphics Paper Tiger Printer $1 ,094

NEW! From Integral Data.

The IDS 460.

We saw this new desktop printer at the NCC 80
and when we saw its features: Correspondence
quality printing, High-resolution graphics capa-
bility, programmable print control functions, and
automatic text justification — we knew that we had
to offer this printer to our cost/features conscious
customers $1,295

The Omni 810 Printer from

Texas Instruments

CENTRONICS PRINTERS

New! The incredible Model 737- Correspondence
and Draft Quality Printing for Under $1,000. This is
the first printer in its class to offer print quality
suitable for text processing, plus the performance
and application flexibility required for data pro-
cessing. $995

737-3 (Serial Interface) $1,045

Tractor Feed Printer- Centronics’ Most Popular
Model. Perfect for the needs of a small business
sytesm. Recommended by Apple and Radio Shack.

$1,079

NEC The First Name in Letter
Quality Printers.

CompuMart offers beautiful print quality with NEC
Spinwriter terminals. The Spinwriters, both KSR
and RO versions, give unsurpassed hard copy
output. CompuMart

offers a complete
range of NEC Spin-
writers— Call our
expert salesforce

HEWLETT-PACKARD’S HP-41 C

Tl Omni 820 Receive-Only (RO) Package. Includes
machine-mounted paper tray and cable. A com-
pressed print option and device forms control are
standard features $2,155

Tl Omni 820 Keyboard Send Receive (KSR) Package
Comes with full ASCII Keyboard with numeric Key-
pad and an EIA cable with autospeed select. $2,395

HP-41C Calculator

$288.00

The System

Memory Modules. For storing programs or up to
2,000 lines of program memory $45.00

“Extra Smart’’ Card Reader. Records programs and

data back onto blank mag-cards $1 99.00

The Printer. Upper and Lower case, High resolution
plotting, Portable Thermal operation $355.00

Application Modules $45.00 EACH

Standard pac:

Statistics,

Math,

Financial &

Surveying

Tl CALCULATORS •

Monitors=

EXCLUSIVE from CompuMart!

^Special Offer. Zenith Color Video
^ Monitor for $379! ,

The perfect monitor for Apple, Atari
and Texas Instruments owners.

NEW FROM SANYO — Four Great Moni-
tors at Low CompuMart Prices.

Sanyo’s new line of CRT data display monitors are
specifically designed for the display of alpha-
numeric or graphic data.

9" Sanyo Monitor $169

12" Sanyo Monitor $289

12" Sanyo Monitor with green screen 5299
13" Sanyo Color Display Monitor 5495

The Tl Programable Calculator —
Super Sale $229.00

NOVATION CAT™

ACCOUSTIC MODEM

• Answer Originate

• 300 Baud

Looks good, works great!

• Bell 108

• Low Profile Design

$179.00

Texas Instruments TI-99/4 Home
Computer

Save $300 on this 16-Bit computer with
monitor

TI-99/4 w/Monitor $889

TI-99/4 w/o Monitor $725

Brand New From Apple for the Apple II

DOS 3.3 Convert disks to 16 sector format for 23%

more storage and faster access $60

Apple Plot. The perfect graphic complement for Visi-
calc. $70

Dow Jones News & Quotes $95

Adventure $35

DOS Tool Kit $75

Apple Fortan $200

New From Videx! — Video Term.

80 column by 24 line 7x9 matrix — plug in compati-
ble board for the Apple II. Price: $325 w/o graphics

EPROM

Options: Graphics EPROM $25

Video Switch Plate, inserts between Apple II
Video and vidoterm board $12

NEW FROM MUSE FOR YOUR APPLE II

The Voice $39.95

Super Text $99.00

Address Book $49.95

S.S.M. Serial & Parallel Apple Interface $225

NEW! ABT’s Numeric Key pad $1 10

C.C.A. Data Management Program for

Apple II $ 99

New from Mountain Hardware — Expan-
sion Accessories for Your Apple.

Introl/X- 10 System $289

Super Talker $299

The Music System $545

ROM plus board w / Keyboard filter $199

New from Microsoft — The Z-80 Softcard $349

Apple III Accessories

Silentype Thermal Printer $525

Disk III $545

12" B&W Monitor $320

Vinyl Carry Case $ 75

Computers

BUY-OF-THE-MONTH
Apple III is Here

Zenith Z-89

The All-In-One-Computer
This is the famous computer system which
up no more space than a terminal alone. The 12"
screen is beautiful and lends itself perfectly to
professional applications thanks to its 25 lines of
80 characters. We know of no other computer
which gives you this many features at such a low
price.

Zenith 48K Z-89 Dual Port List $2,895

CompuMart $2,695

Got It!

Apple III System Packages

Apple III Information Analyst Option A.

Includes: Apple III System with 96K RAM memory,
Information analyst configuration package, 12" B&W
monitor for Apple III $4,340

Apple III Information Analyst Option B.

Same as Option A plus: Disk 11 for Apple III $4,885

Apple III Information Analyst Option C.

Same as Option A plus: Disk 1 1 for Apple III, Silen-

type Thermal Printer for Apple III $5,410

Apple III Software

Visicalc III $250

Mail List Manager $250

Business Basic $250

PASCAL $250

FORTRAN $250

System Software & Manuals $250

Z 19 Smart Video Terminal

CompuMart

List $995

$895

LUMIVIUUUm:

Buy Direct from the largest Commodore dealer in
the country, and the very first Commodore
distributor in the U.S. Buy from the experts Buy
from CompuMart.

Commodore — We have everything
that Commodore manufactures. In
stock for Immediate Delivery!

Call CompuMart now for low
prices and special deals.

ATARI 800 Personal Computer System.

Comes with 800 Operators Manual, 16K RAM Mem
ory module, 10K ROM Operating System, power
supply, TV Switch Box. $1080

We have a complete inventory of
Apple computers,
peripherals and software/

... J I I I II I I M
U II I II 111 I II

imViVnViY |

Introducing the HP-85
$3,145

Hewlett-Packard’s Personal
Computer for Industry.

This extremely portable
computer features ex-
tended BASIC to solve your problems quickly and
efficiently along with an advanced graphics sys-
tem to enhance communication.

NEW from Hewlett-Packard

HP 82900-Series Flexible Disk Drives for the

HP-85

These 4 new Flexible Disk Drives provide fast on-line
storage using flexible disks

*HP 82901 M. Supplies approx. 540K bytes of on-line
storage. $2,500

*HP 82902M. Approx. 270K bytes of on-line storage.

$1,500

*HP 82901 S. Supplies an additional 540K bytes when
connected to an HP 82901 M or an HP 82902M.

$ 2,200

*HP 829025. Supplies an additional 270K bytes when
connected to an HP 82901 M or an HP 82902M.

$1,300

The Hewlett-Packard 7225A. High Ouality/Low Cost
Graphics Plotter. $2,050

Call our expert sales force for complete product
specifications.

\

Super Sale on Exidy Sorcerer

List Price

Sale!

16K Sorcerer

$1,295

$999

Parallel Data Cable

$35

$20

Development PAC

$99

$85

Word Processing PAC

$199

$169

S-100 Expansion Unit

$419

$389

s

Lots of other Sorcerer accessories in stock at low
prices — CALL!

PERIPHERALS

Atari 410 Program Recorder (FREE w/ purchase of
Atari 800)

Atari 810 Disk Drive
New Dual Disk double density
825 Printer (Centronics 737)

RS232 Interface w/ Cable
NEW! Light Pens
Call for New Software

ROCKWELL AIM 65

The single board development system
that’s perfect in the classroom or lab.

Our AIM System includes: 4K AIM with BASIC
interpreter assembler, Power Supply, Cassette
recorder & Enclosure $799.

4K AIM - 65 $499

PL65 High Level Language $125

Paper for the AIM (roll) $ 2.!

Rockwell’s 4-slot Motherboard (SALE) $175

CompuMart’s Microflex 65 System for your AIM
Includes: Adapter Buffer Module w/ 4-slot module
stack, 8K RAM module, 16K PROM/ROM module,
Asynchronous communications Interface, & Power
Supply $1,299

Call or write for
our complete
Microflex 65
brochure

Phones
open from
8:30 a m to 5 30
pm EST, Mon Fri
PO.s accepted from
D&B rated companies -
shipment contingent upon receipt
of signed purchase order • All prices
are subject to change without notice • Most
items in stock for immediate shipment— call
tor delivery quotation • In the Ann Arbor area? Our
retail store is open 1 1:00 a.m. to 7:00 p m. Tues.-Fri ,
10:00 a m to 5 00 p.m. Saturdays (closed Sun and Mon.)

COMPUMART

270 THIRD STREET DEPT 130 CAMBRIDGE, MA. 02142

Member Computer Dealers Assoc^

v* Reader Service index— page 241

We’ve had a reputation for dependability since 1971

The Dual
Processor Board

uses an 8088 CPU for
true 16 bit power with an 8
bit bus, and an 8085 for compati-
bility with CP/M and 8080 software.
SPECIAL LOW PRICES: $295 unkit, $425
assm (both operate at 5 MHz); $525 qualified
under the high - reliability Certified System
Component program ( with 5 MHz 8085 ,
6 MHz 8088).

The Z80A
CPU Board

includes on-board
fully maskable interrupts
for interrupt- driven systems, pro-
vision for adding upto8K of on-board EPROM,
IEEE compatible 16/24 bit extended addressing,
and much more. 4 MHz standard operation, but
also works with 6 MHz Z80s. $225 unkit, $295
assm $395 CSC.

Throughput is the Only True Measure

of Computer Performance.

Want a 300% improvement in throughput compared to 2 MHz
systems? IEEE-compatible CompuPro boards are designed from the
ground up to operate at 6 MHz and beyond, dramatically increasing
computing power and performance. Don’t settle for less . . . select
high speed, high reliability S-100 products from CompuPro.

HIGH SPEED S-100 MEMORY and MOTHERBOARDS

RAM XX (with bank select AND extended addressing) is the perfect match for either CPU board — thanks to
fully static operation, extremely low power consumption, and complete IEEE spec compatibility. All unkit and
assembled memories work up to 5 MHz, while Certified System Component boards run up to 8 MHz and are
guaranteed to work with 6 MHz Z80s. All CompuPro motherboards work up to 10 MHz.

unkit assm CSC

16K RAM XX-16 $349 $419 $519

24K RAM XX-24 $479 $539 $649

32K RAM XX-32 $649 $699 $799

20 slot motherboard with edge connectors $174 $214 n/a

12 slot motherboard with edge connectors $129 $169 n/a

6 slot motherboard with edge connectors $89 $129 n/a

SEE COMPUPRO PRODUCTS IN PERSON AT COMPUTER STORES WORLD-
WIDE, OR WRITE US DIRECT IF THERE’S NO STORE IN YOUR AREA.

TERMS: Cal res add tax. Allow 5% for shipping, excess refunded. VISA®/Mastercard® orders call (415) 562-0636, 24
hours. Please include street address for UPS delivery. Sale prices good through cover month of magazine, other prices subject
to change without notice.

Bldg. 725, Oakland Airport, CA 94614

224 Microcomputing, October 1980

MCft-

ELECTRONICS

*>44

INTEGRATED CIRCUITS

P.0. Box 4430S
Santa Clara, CA 95054
Will calls: 2322 Walsh Ave.
(408) 988-1640

Same day shipment. First line parts only. Factory tested
Guaranteed money back. Quality IC’s and other compo-
nents at factory prices.

7400TTL

7 WON
7402N
7W4N
7409N
74 1 ON
7414N
7420N
7427N
7430N
7442N
7445N
7447N
744EN
7450N
7474N
7475N
7485N
7489N
7490N
7492N
7493N
7495N
741 00N
74107N
74121N
741 23N
74125N
74 MSN
741 SON
74151N
71154N
74157N
74161N
74162N
74I63N
74174N
741 75N
74190N
74192N
74193N
74221N
74298N
74365N
74366N
7436 7N

74LSOON

74LS02N

74LS04N

74LSOSN

74LS08N

74LS10N

74LS13N

74LS14N

74LS70N

74LS22N

74LS28N

74LS30N

74LS33N

741S38N

74LS74N

741S75N

74LS90N

741S93N

74LS9SN

74LS107N

74LS112N

74LS113N

74LS132N

74LS136N

74LS151N

74LS155N

741S157N

74LS162N

74LS163N

74LS174N

74LS190N

741S221N

74LS258N

74LS367N

UNEAR

CA3045

I.M323K 5 S 95
i IM320K 12 150
I IM320K 15 1 50
LM320T 5 1 35

LM320T-8 1 35

LM320T 12 135
t LM320T 15 135
i IM324N 1 40
I IM339N 1 00
IM340K-5 1 35

LM340K 8 1 35

IM340K 1? 135
l LM340K 15 135
LM340K 24 1 35
l IM340T 5 1 25

i LM340T 8 1 25

i IM340T 12 125
I LM340T-1 5 125
LW340T-18 125
LM340T-24 1 25
l LM350 7 50

I LM377 3 50

i LM379 5 00

) LM380N 1 00
> LM381 1 60

I LM382 1 60

I LM703M 65
i LM709H 28
' LM723H N 50
I LM733N 85
I LM741CH 35
I LM741N 30
I LM747H/N .75
' LM748N 35
i LM1303N 1 75

LM1304

I 27

96 LM1305

95 LM1307 l uo

115 LM 131 0 2 75

87 LM1458 47

85 LM1812 7 50

2 75 LM1B89 3 00

1 65 LM2111 1 75

89 LM2902 2 25

89 LM3900N 50

.89 LM3905 1 75

IM3909N 95

MC1458V 50

35 NE550N 1 00

35 NE555V 39

55 NE556A 85

40 NE565A 1 00

45 NE566V 150

45 NES67V i 00

55 NE570B 4 75

1 25 78L05 60

45 78108 60

45 78M05 85

45 75108 1 75

45 75491 CN 50

75 75492CN 55

75 75494CN 89

I 25
I 00

1 00 A la 0 CONVERTER

1 00 80388 4 50

1 10 8700CJ 13.95

65 8701CN 2200

65 8750CJ 13 95

45 LD130 9 95

89 9400CJV F

65 ICL7103

1.10 ICL7107

C04026

eg in? i

CD4028

C04029

CD4030

C04035

CD4040

C04042

C04043

CD4044

C04046

COW49

CD 4050

CD4051

CD4060

CD4066

CO 4068

CO 4069

CO 4070

CD 4071

CO 4072

CD4073

CD4075

CD4076

CO 4078

CO 4081

C04082

CD4116

CD4490

C04507

CO 4508

C04510

C04511

C04515

C04516

CO 4518

CD4520

CD-4527

CD4528

C04553

C04566

CD4583

CD4585

CD40192

74COO

74C04

74C10

74C14

74C20

74C30

74C48

74C74

74C76

74C90

74C93

74C154

74C160

74C175

74C192

74C221

74C905

74C906

74C914

74C922

74C923

74C925

74C926

74C927

2 50 4116 200ns 7 95 CONNECTORS

66 8 4116 200ns 49 00 30 pm edge

85 2513B 6 30 44 pm edge

135 MM5262
45 MM5280
1 35 MM5320
1 35 MM5330
85 P0411D-3
85 PD411D4
85 P5101L
1 67 4200A
45 82S2S
49 91L02A
1 13 HD0165-5
1 42 MM57100
71 GIAY38500-1

1C SOCKETS
Samar Tin low Pro/ile
, PIN 1 UP PIN 1UP

16 16 28 42

$67 50
77 50
60 00
70 00
14 95
29 95

pm «« 20

9 95 WIRE WRAP LEVEL 3

KEYBOARDS

56 <ey ASCII keyboard kit
Fully assembled
53 key ASCII keyboard kit
Fully assembled
Enclosure Plastic
Metal Enclosure

LESS
Red T0 18

Greer. Yeilow T018

Green Orange. Yellow Jumbo 25
CHpllle LED Mounting Clips 8 $125
(spec-ly red, amber, green, yellow, dear)

CONTINENTAL SPECIALTIES la slock

45 416
45

« CLOCKS

45 MM5311
1 65 MM5312
♦0 MM5314
35 MM 5369
35 MM5841
47 MM5865
5 50 CT7010
* CT7015

MAX-100 8 41(11 Frag. Clr

5 50 1 MHz

3 90 2 MM:

3.90 <M«z
2 10 5 MHz

14 45 10 MHa

7 95 18 “Hi

8 95 20 Ml”
8 95 32JMH*

4 50 Complete line ol AP Products in slock

4 25 MM5375AA.N 3 90 32788*

1 02 MM5375AG N 4 90 \ 8432 MHz

94 7205 16 50 3.5795 MHz

2 52 7207 7 50 2 0100 MHz

1 10 7208 15 95 2 097152 MHz

1 02 7209 4 95 2 4576 MHz

1 02 0SM26CN 3 75 3 2768 MHz

'51 DS0056CN 3 75 5 0688 MHz

a 3 MM53 ' 04

2 25 MICROPROCESSOR 6 5536 MHz

SPECIAL PRODUCTS

MM5865 Stopwatch Timer
with 10 pg spec.

PC board

Switches Mom Pushbutton
3 pos slide
Encodar H00165 5
Paralronics 100A Logic
Analyzer $4

Model 10 Trigger
Expander Kit S2

Model 150 Bus
Grabber Kit

$369 00

$23 95

2 35 6502
110 6504

3 00 6522
35 6800
40 6802
35 6820

1 95 6850

E 8MM

35 8085

2 25 8086
85 Z«0

10 95 14 31818 MHz 4 25

9 95 18 432 MHz 4 50

9 95 22 1184 MHz 4 50

11 95 KEYBOARD ENCOOERS

4 95 AY5 2376

595 AY5-360O
595 AY5-9100
1295

75 00 740922

9 95 74C923

11 95 H00165-5

$12 50
17 95
10 50
16 50

Clock Calendar Kll
2.5 MHz Frequency
Counter Kll
30 MHz Frequency
Counter Kit

TRANSFORMERS

6V 300 ma
12 Volt 300 ma translormer 1 25

3 75
2 95
350

3 45 OB25P
4S5 DB25S
6 95 Cow
15 00 ne “ e

1050

RS232

I 75 280A

1 75 82'2

1 75 8214

3 00 8216

2 00 8224

1 35 8228

2 75 Si

2 50 8253

6 00 8255

75 8257

1 96 8259 is »

6 OO 18020P ptal 17 95

7 50 1861P 1150 7

6 95 C0P1802C0 28 95 SlopwMch Kit

6 95 CD PI 8020 35 00 Aulo Clock Kit

CD P 1 861 15 95 Digital Clock Kll

10 95

DE9S
DA ISP
DA15S
Complete Set

74.96

26.95

17.95

1 10

CA3081
CA3G82
CA3089
LM301 AN/AH .35

LM305H 87

LM307N 35

LM306N 100

LM30SK 1 50

LM311H/N 90

LM317T/K 3 75

LM318 1 35

LM320K-5 1 50

CMOS

C04000
CD40Q1
CD 4002
C04006
CD4O07
CD4008
CD4009
CD4O10
CD401I
CD4012
CD4013
CD40I4
CD401S
CD4016
C04017
C04018
CO4019
CO402O
CO 4021
004022
CD4023
CO4024
CD4025

65

65

1.25

UART/FIFO

AYS- 1013
AYS-1014
3341

5 M (less PROMS) $89 00

J SO Moth era oar d $39 00

6 » (nmdir Board $15 00

12 6V CT 6
12V 250 ma wall plug
12V CT 250 ma wall piui
24V CT 400 ma
10V 1 2 amp wall plug
12V 6 amp

12V 500 ma wall plug

DISPLAY LEOS

MAN1 CA 270 2 90

MAN3 CC 125 39

MAN7&74 CA.CA 300 1 00

01704 CC 300 1 25

0L707/DL707R CA 300 1 00

DL727<728 CA/CC 500 1 90

CA/CC 600 1 95
CC 600 1 95
CC 357 70

COCA 500 1 35
COCA 500 90

CC/CA 800 2 20

DL747/750

DL750

FND359

FN050Q 507

FND503-510

FND800/807

50 PROM RESISTORS 'A

3 00 1702 A 4 95 10 per type 0

5 50 2S13B upper case 8.75 ,£> type 025
3 1 0 2708 7 75 —

3 50 7716T1 18.00

3 20 2716 Intel 23 00

1 69 8/2716 Intel 160 00

2 75 273? 65 00

1 69 2758 22 SO

1 69 8741A 60 00

8748

8748 8

MOS/MEMORY RAN8755A

2101 1 2 95 N82S23

95 N82S123
1 34 N62S126

I 60 N82S129

4 95 N82S131

3 75 N82S136

3 75 N82S137

3 95 OM8577

2102-1
2102AI-4
2102AN-2L
2104A-4
21078 4
2111-1
2112-2
21 14L 300ns 6 75 8223
21 14L 450ns 5 95

5%

100 per type 015
1000 per type .012
350 piece pack
5 per type 6 75
Vi wan 5% par type .05

65 00 Talaeidao Terminal
60 00 Model 91? $645 00

55 00 Model 970 $945 00

2 95

6 60 Tiny la lie Eapenmenton Kit
S10 00

DG8 Fluorescent
DG10 Fluorescent
10 digit display
7520 Clalrex photocells
TIL3H Hex
MAN 3640

MAN4640
MAN47I0
MAN4740
MAN6640
MAN6710
MANS 740

39
950
CC 30 1 10
CA 40 1 20
CC 40 1 20
CA 40 95

CC 40 1 20
CC 56 2 95
CA 60 1.35
CC 60 1 35

8 50
850

8 75 BSR Controller $39 95

8 75 Conneclysurcompurec to »ie BSR Home Control
? 90 System Computer compiled uhrasomc Irani
7 go Tune* toi ywr 8SR Sohware to 1802 user

MA1002A

MA10O7F

MA1012A

102P3 Iranstormer

MA1012A Transformer

PROM Eraser

assembled. 25 PROM capacity $37.50
(with timer $69.50) 6 PROM capacity OSHA/
UL version $69.50 (with timer $94.50)

Z80 Microcomputer

16 bit I/O. 2 MHz clock. 2K RAM, ROM Bread-
board space. Excellent for control. Bare Board
$28.50. Full Kit $99.00. Monitor $20.00. Power
Supply Kit $35.00. Tiny Basic $30.00

S-100 Computer Boards

8K Static Godbout Econo IIA Kit 145.00
1 6K Static Godbout Econo XIV Kit 285.00
24K Static Godbout Econo VIIA-24 Kit 435.00
32K Static Godbout Econo X-32 Kit 575.00
16K Dynamic RAM Kit 199.00

32K Dynamic RAM Kit 310.00

64K Dynamic RAM Kit 470.00

Video Interface Kit $135.00

80 1C Update Master Manual $55.00

Comp. 1C data selector. 2700 pg. master reference
guide. Over 51 ,000 cross references. Free update
service through 1980. Domestic postage $3.50.
Modem Kit $60.00
State of the art, orig., answer. No tuning neces-
sary. 103 compatible 300 baud Inexpensive
acoustic coupler plans included.

LRC 7000 + Printer $389.00

40/20 column dot matrix impact, std. paper.

Interface all personal computers.

64/40/32/20 version $405.00. Optional cables
available.

LRC 7000 printer interface cable for Super Elf
with software $26.00

NiCad Battery Fixer/Charger Kit

Opens shorted cells that won’t hold a charge
and then charges them up, all in one kit w/full
parts and instructions. $7.25

Rockwell AIM 65 Computer

6502 based single board with full ASCII keyboard
and 20 column thermal printer. 20 char, alphanu-
meric display. ROM monitor, fully expandable.
$375.00 . 4K version $450.00 4K Assembler
$85.00 8K Basic Interpreter $100.00
Special small power supply for AIM65 assem. in
frame $54.00. Complete AIM65 in thin briefcase
with power supply $499.00. Molded plastic
enclosure to fit both AIM65 and power supply
$47.50. Special Package Price: 4K AIM, 8K Basic,
power supply, cabinet $599.00
Al M65/KI MA/IM/Super Elf 44 pm expansion
board; 3 female and 1 male bus. Board plus 3
connectors $22.95.

60 Hz Crystal Time Base Kit $4.40

Converts digital clocks from AC line frequency
to crystal time base. Outstanding accuracy.

Video Modulator Kit $8.95

Convert TV set into a high quality monitor w/o
affecting usage. Comp, kit w/full instruc.

Multi-volt Computer Power Supply

8v 5 amp, ±18v .5 amp, 5v 1.5 amp, 5v
.5 amp, 12v .5 amp, 12v option. ±5v, ±12v
are regulated. Basic Kit $29.95. Kit with chassis
and all hardware $43.95. Add $4.00 shipping. Kit
of hardware $14.00. Woodgrain case $10.00.
$1.50 shipping.

RCA Cosmac 1802 Super Elf Computer $106.95

Compare features before you decide to buy any
other computer. There is no other computer on
the market today that has all the desirable bene-
fits of the Super Elf for so little money. The Super
Elf is a small single board computer that does
many big things. It is an excellent computer for
training and for learning programming with its
machine language and yet it is easily expanded
with additional memory. Full Basic. ASCII
Keyboards, video character generation, etc.
Before you buy another small computer, see if it
includes the following features: ROM monitor,
State and Mode displays; Single step; Optional
address displays; Power Supply; Audio Amplifier
and Speaker; Fully socketed for all IC’s; Real cost
of in warranty repairs; Full documentation.

The Super Elf includes a ROM monitor for pro-
gram loading, editing and execution with SINGLE
STEP for program debugging which is not in-
cluded in others at the same price. With SINGLE
STEP you can see the microprocessor chip opera-
ting with the unique Quest address and data bus
displays before, during and after executing in-
structions. Also, CPU mode and instruction cycle
are decoded and displayed on 8 LED indicators.
An RCA 1861 video graphics chip allows you to
connect to your own TV with an inexpensive video
modulator to do graphics and games. There is a
speaker system included for writing your own
music or using many music programs already
written. The speaker amplifier may also be used
to drive relays for control purposes.

plus load, reset, run. wait, input, memory pro-
tect, monitor select and single step. Large, on
board displays provide output and optional high
and low address There is a 44 pm standard
connector slot for PC cards and a 50 pin connec-
tor slot for the Quest Super Expansion Board.
Power supply and sockets tor all IC’s are in-
cluded in the price plus a detailed 127 pg. instruc-
tion manual which now includes over 40 pgs. of
software info, including a series of lessons to
help get you started and a music program and
graphics target game. Many schools and univer-
sities are using the Super Elf as a course of study.
OEM’s use it for training and R&D.

Remember, other computers only offer Super Elf
features at additional cost or not at all. Compare
before you buy. Super Elf Kit $106.95, High
address option $8.95, Low address option
$9.95. Custom Cabinet with drilled and labelled
plexiglass front panel $24.95. All metal Expan-
sion Cabinet, painted and silk screened, with
room for 5 S-100 boards and power supply
$57.00. NiCad Battery Memory Saver Kit $6.95.
All kits and options also completely assembled
and tested.

Questdata. a software publication for 1802 com-
puter users is available by subscription for
$12.00 per 12 issues. Single issues $1.50. Is-
sues 1-12 bound $16.50.

Tiny Basic Cassette $10.00, on ROM $38.00,
original Elf kit board $14.95. 1802 software;
Moews Video Graphics $3.50. Games and Music
$3.00, Chip 8 Interpreter $5.50.

A 24 key HEX keyboard includes 16 HEX keys

Super Expansion Board with Cassette interface $89.95

This is truly an astounding value! This board has
been designed to allow you to decide how you
want it optioned The Super Expansion Board
comes with 4K of low power RAM fully address-
able anywhere in 64K with built-in memory pro-
tect and a cassette interlace Provisions have
been made for all other options on the same
board and it fits neatly into the hardwood cabinet
alongside the Super EM. The board includes slots
for up to 6K of EPROM (2708, 2758. 2716 or Tl
2716) and is fully socketed. EPROM can be used
for the monitor and Tiny Basic or other purposes.
A IK Super ROM Monitor $19.95 is available as
an on board option in 2708 EPROM which has
been preprogrammed with a program loader/
editor and error checking multi file cassette
read/write software, (relocatable cassette file)
another exclusive from Quest. It includes register
save and readout, block move capability and
video graphics driver with blinking cursor. Break

points can be used with the register save feature
to isolate program bugs quickly, then follow with
single step. If you have the Super Expansion
Board and Super Monitor the monitor is up and
running at the push of a button.

Other on board options include Parallel Input
and Output Ports with full handshake They
allow easy connection of an ASCII keyboard to the
input port RS 232 and 20 ma Current Loop for
teletype or other device are on board and if you
need more memory there are two S-1 00 slots for
static RAM or video boards. Also a IK Super
Monitor version 2 with video driver for full capa-
bility display with Tiny Basic and a video interface
board Parallel I/O Ports $9.85. RS 232 $4.50,
TTY 20 ma l/F $1.95, S-100 $4.50. A 50 pin
connector set with ribbon cable is available at
$15.25 for easy connection between the Super
Elf and the Super Expansion Board.

Power Supply Kit for the complete system (see

Multi-volt Power Supply ).

Announcing Quest Super Basic— SECOND GENERATION

A new enhanced version of Super Basic now Enhancements include increased speed, built-
available. Quest was the first company worldwide in provisions for Stringy Floppy, Floi

to ship a full size Basic for 1802 Systems. A
complete function Super Basic by Ron Cenker

including floating point capability with scientific
notation (number range ± . 1 7E 38 ) , 32 bit integer
±2 billion; multi dim arrays, string arrays; string
manipulation; cassette I/O; save and load, basic,
data and machine language programs; and over

in provisions for Stringy Floppy, Floppy Oise,
Printer Driver, I/O, user definable command
library and statement renumbering.

Easily adaptable to most 1802 systems. Re-
quires 16K RAM minimum for Basic and user
programs. Source listing for both Serial and
Parallel I/O included.

Super Basic on Cassette $40.00.

Gremlin Color Video Kit $69.95

32 x 16 alpha/numerics and graphics; up to 8
colors with 6847 chip; IK RAM at E000. Plugs
into Super Elf 44 pin bus. No high res. graphics.
On board RF Modulator Kit $4.95

Elf II Adapter Kit $24.95

Plugs into Elf II providing Super Elf 44 and 50 pin
plus S-100 bus expansion (With Super Ex-
pansion). High and low address displays, state
and mode LED’s optional $18.00,

1802 16K Dynamic RAM Kit $149.00

Expandable to 32K. Hidden refresh w/clocks up to 4
MHz w/no wait states. Addl. 16K RAM $63.00
Super Elf 44 pin expansion board; 3 female and 1
male bus. Board plus 3 connectors $22.95
Tiny Basic Extended on Cassette $15.00

(added commands include Stringy, Array. Cas-
sette I/O etc.)

S-100 4-Slot Expansion $ 9.95

Super Monitor VI. 1 Source Listing $15.00

Super Color S-1 00 Video Kit $129.95

Expandable to 256 x 192 high resolution color
graphics. 6847 with all display modes computer
controlled. Memory mapped IK RAM expanda-
ble to 6K. S-1 00 bus 1802. 8080. 8085, Z80 etc.

Editor Assembler $25.00

(Requires minimum of 4K for E/A plus user
source)

1802 Tiny Basic Source listing $19.00

Super Monitor V2. 0/2.1 Source Listing $20.00

TERMS: $5.00 min. order U.S. Funds. Calif residents add 6% tax.

$10.00 min. order BankAmericard and Master Charge and COD. $1.00 insurance optional.
Shipping charges will be added on charge cards.

FREE: Send for your copy of our NEW 1980
QUEST CATALOG. Include 48c stamp.

is* Reader Service index-page 241

Microcomputing, October 1980 225

“THE BIG BOARD”

OEM - INDUSTRIAL - BUSINESS - SCIENTIFIC

SINGLE BOARD COMPUTER KIT!

Z-80 CPU! 64K RAM!

THE FERGUSON PROJECT: Three years in the works, and maybe too good to be true. A tribute to hard headed, $ Jk QQ Q (64K KIT
no compromise, high performance, American engineering! The Big Board gives you all the most needed ** BASIC I/O)

computing features on one board at a very reasonable cost. The Big Board was designed from scratch to run the
latest version of CP/M*. Just imagine all the off-the-shelf software that can be run on the Big Board without any
modifications needed! Take a Big Board, add a couple of 8 inch disc drives, power supply, and an enclosure; and
you have a total Business System for about 1/3 the cost you might expect to pay.

FEATURES: (Remember, all this on one board!)

SIZE: 8Vj x 1 3 3 /« IN.

SAME AS AN 8 IN. DRIVE.
REQUIRES: +5V @ 3 AMPS
+ - 12V @ .5 AMPS.

64K RAM

Uses industry standard 4116 RAM S. All 64K is available to the user, our VIDEO
and EPROM sections do not make holes in system RAM. Also, very special care
was taken in the RAM array PC layout to eliminate potential noise and glitches.

Z-80 CPU

Running at 2.5 MHZ. Handles all 4116 RAM refresh and supports Mode 2
INTERUPTS. Fully buffered and runs 8080 software.

SERIAL I/O (OPTIONAL)

Full 2 channels using the Z80 SIO and the SMC 81 16 Baud Rate Generator. FULL
RS232! For synchronous or asynchronous communication. In synchronous
mode, the clocks can be transmitted or received by a modem. Both channels can
be set up for either data-communication or data-terminals. Supports mode 2 Int.
Price for all parts and connectors: $85.

80 x 24 CHARACTER VIDEO

With a crisp, flicker-free display that looks extremely sharp even on small
monitors. Hardware scroll and lull cursor control. Composite video or split video
and sync. Character set is supplied on a 2716 style ROM, making customized
fonts easy. Sync pulses can be any desired length or polarity. Video may be
inverted or true.

FLOPPY DISC CONTROLLER

Uses WD1771 controller chip with a TTL Data Separator for enhanced
reliability. IBM 3740 compatible. Supports up to four 8 inch disc drives. Directly
compatible with standard Shugart drives such as the S A800 or SA801 . Drives can
be configured for remote AC off-on. Runs CP/M* 2.2.

FOUR PORT PARALLEL I/O (OPTIONAL)

Uses Z-80 PIO. Full 16 bits, fully buffered, bi-directional. User selectable hand
shake polarity. Set of all parts and connectors for parallel I/O: $29.95

BASIC I/O

Consists of a separate parallel port (Z80 PIO) for use with an ASCII encoded
keyboard for input. Output would be on the 80 x 24 Video Display.

REAL TIME CLOCK (OPTIONAL)

Uses Z-80 CTC. Can be configured as a Counter on Real Time Clock. Set of all
parts: $14.95

SYSTEM COMPARISON

64K RAM KIT $370.00

80 x 24 Video Kit 365.00

Floppy Disk Controller Kit 235.00

Z-80 CPU Kit 185.95

SER & PAR. I/O 129.95

S-100 Mother Board 45.00

SUB TOTAL $1330.90

Talk about bangs per buck! The prices shown for
SI 00 kits were taken from the July 1980 BYTE.
This will give some basis for comparison between
the Big Board and a similar system
implementation on the S100 Buss.

CP/M* 2.2 FOR BIG BOARD

The popular CP/M* D.O.S. modified by MICRONIX
SYSTEMS to run on Big Board is available for $150.00.

FIRST TIME OFFERED!

PFM 3.0 2K SYSTEM MONITOR

The real power of the Big Board lies in its PFM 3.0 on board monitor. PFM commands include: Dump Memory, Boot CP/M*. Copy, Examine, Fill Memory, Test Memory. Go To.
Read and Write I/O Ports, Disc Read (Drive, Track, Sector), and Search. PFM occupies one of the four 2716 EPROM locations provided. It does not occupy any of the 64K of
system RAM!

Digital Research Computers

** (OF TEXAS) r

P.O. BOX 401565 • GARLAND, TEXAS 75040 • (214) 271-3538

TERMS: Initial shipments will be made approximately 3 to 5 weeks after we
receive your order. VISA, MC, cash accepted. We will accept COD'S (for the
Big Board only) with a $75 deposit. Balance UPS COD. The $75 deposit
assures your place in line for the initial production run of Big Board.

TRADEMARK OF DIGITAL RESEARCH. NOT ASSOCIATED WITH DIGITAL RESEARCH OF CALIFORNIA, THE SUPPLIERS OF CPM SOFTWARE

** 1 TO 4 PIECE DOMESTIC USA PRICE.

DIGITAL RESEARCH COMPUTERS

(214) 271-3538

32K S-100 EPROM CARD

NEW!

USES 2716 s

Blank PC Board - $34

ASSEMBLED & TESTED
ADD $30

SPECIAL: 2716 EPROM s (450 NS) Are $19.95 EA. With Above Kit.

7. Any or all EPROM locations can be
disabled.

8. Double sided PC board, solder- masked,
silk-screened.

9. Gold plated contact fingers.

10. Unselected EPROM’s automatically
powered down for low power.

11. Fully buffered and bypassed.

12. Easy and quick to assemble.

KIT FEATURES:

1. uses +5V only 2716 (2Kx8) EPROM’s.

2. Allows up to 32K of software on line!

3. IEEE S-100 Compatible.

4 Addressable as two independent 16K
blocks.

5. Cromemco extended or Northstar bank
select.

6. On board wait state circuitry if needed.

,0

16K DYNAMIC RAM PARTIALS
^ \ INTEL 2108 8 K X 1 RAMS 4

K /

v 8 FOR $9.95 32 FOR $35

V FACTORY PRIME!

Huge special purchase of INTEL Dynamic RAM’s. These
are 2108-4, 300NS, 8K, Ceramic DIP. The 2108 is the
INTEL 2116 (16K) tested for either upper or lower 8K only.
These are factory prime. Full Spec. See INTEL 1978 Cat.
for details or Memory Design Handbook for application
data. Both IMSAI and EXTENSYS did mfa. S-100 RAM
boards using these devices. — P.S. These devices will not
work in the SD EPANDORAM™. Please specify upper or
lower 8K. (SI 626 or SI 627) . A super easy RAM to interface
to a Z80, 16 PIN DIP.

FOR

4MHZ

LOW POWER - 300NS 8 FOR

2114 RAM SALE! *44

4K STATIC RAM'S. MAJOR BRAND, NEW PARTS.

These are the most sought after 2114’s, LOW POWER and 300NS FAST.

8 FOR $44

16K STATIC RAM KIT-S 100 BUSS

PRICE CUT!

16K STATIC RAM SS-50 BUSS

PRICE CUT!

FULLY STATIC!

BLANK PC BOARD W/DATA-$33
LOW PROFILE SOCKET SET-$12
SUPPORT IC’S & CAPS-S19.95

KIT FEATURES:

1. Addressable as four separate 4K Blocks.

2. ON BOARD BANK SELECT circuitry. (Cro-
memco Standard 1 ). Allows up to 512K on line!

3. Uses 2114 (450NS) 4K Static Rams.

4 - ON BOARD SELECTABLE WAIT STATES.

5 Double sided PC Board, with solder mask and
silk screened layout. Gold plated contact fingers

6 All address and data lines fully buffered ASSEMBLED & TESTED-ADD $35

7. Kit includes ALL parts and sockets.

8. PHANTOM is jumpered to PIN 67.

9. LOW POWER: under 1.5 amps TYPICAL from
the +8 Volt Buss.

10. Blank PC Board can be populated as any
multiple of 4K.

FOR 2MHZ
ADD $10

FOR SWTPC
6800 BUSS!

OUR #1 SELLING
RAM BOARD!

ASSEMBLED AND
TESTED - $35

KIT FEATURES:

1 Addressable on 16K Boundaries

2 Uses 2114 Static Ram
3. Fully Bypassed

4 Double sided PC Board Solder mask
and silk screened layout
5. Ail Parts and Sockets included
6 Low Power: Under 1.5 Amps Typical

BLANK PC BOARD— $30 COMPLETE SOCKET SET-
SUPPORT IC'S AND CAPS— $19.95

$12

STEREO! / V£-( V/

S-100 SOUND COMPUTER BOARD

16K EPROM CARD-S 100 BUSS

COMPLETE KIT!

$Q495

(WITH DATA MANUAL)

At last, an S-100 Board that unleashes the full power of two
unbelievable General Instruments AY3-8910 NMOS computer
sound IC’s. Allows you under total computer control to
generate an infinite number of special sound effects for
games or any other program. Sounds can be called in BASIC,

ASSEMBLY LANGUAGE, etc.

KIT FEATURES:

★ TWO Gl SOUND COMPUTER IC’S.

★ FOUR PARALLEL I/O PORTS ON BOARD.

★ USES ON BOARD AUDIO AMPS OR YOUR STEREO.

★ ON BOARD PROTO TYPING AREA.

★ ALL SOCKETS. PARTS AND HARDWARE ARE INCLUDED.

★ PC BOARD IS SOLDERMASKED, SILK SCREENED. WITH GOLD CONTACTS.

★ EASY. QUICK. AND FUN TO BUILD. WITH FULL INSTRUCTIONS.

★ USES PROGRAMMED I/O FOR MAXIMUM SYSTEM FLEXIBILITY
Both Basic and Assembly Language Programming examples are included.

SOFTWARE:

SCL'“ is now available 1 Our Sound Command Language makes writing Sound Effects programs
a SNAP 1 SCL’“ also includes routines for Register-Examine-Modify, Memory-Examine-Modify.
and Play-Memory SCL 1 ” is available on CP/M* compatible diskette of 2708 or 2716. Diskette -
$24.95 2708 - $19.95 2716 - $29.95 Diskette includes the source EPROM’S are ORG at

E000H.

BLANK PC
BOARD W/DATA
$31

BLANK PC BOARD - $28

USES 2708’s!

Thousands of personal and business systems aiuund the world use this boara with
complete satisfaction. Puts 16K of software on line at ALL TIMES 1 Kit features a top
quality soldermasked and silk-screened PC board and first run parts and sockets. Any
number of EPROM locations may be disabled to avoid any memory conflicts Fully
buffered and has WAIT STATE capabilities.

ASSEMBLED AND FULLY
TESTED — ADD $30

OUR 450 NS 2708’S
ARE $8.95 EA. WITH
PURCHASE OF KIT

RCA CMOS COMPUTER CHIP SET

INCLUDES:

1- CDP1802CD CPU I-CDPI861CD VIDEO 1C

2- CDP1822CE 256 x 4 RAM 1-CDP1862CE COLOR GEN.
1-CDP1858CE 4 BIT LATCH 1-CDP1863CE SOUND GEN.

COMPLETE SET $45 LIMITED QTY

NEW! G.l. COMPUTER SOUND CHIP

AY3-8910. As featured in July. 1979 BYTE! A fantastically powerful Sound & Music
Generator. Perfect for use with any 8 Bit Microprocessor. Contains: 3 Tone Channels.
Noise Generator, 3 Channels of Amplitude Control. 16 bit Envelope Period Control, 2-8
Bit Parallel I/O. 3 D to A Converters, plus much more! All in one 40 Pin DIP. Super easy
Interface to the S-100 or other busses

SPECIAL OFFER: $14.95 each Add $3 for 60 page Data Manual.

Digital Research Computers

^ (OF TEXAS) r

P.O. BOX 401565 • GARLAND, TEXAS 75040 • (214) 271-3538

TERMS: Add $1.25 postage. We pay balance. Orders under $15 add 75C
handling. No. C.O.D. We accept Visa and MasterCharge. Tex. Res. add 5%
Tax. Foreign orders (except Canada) add 20% P & H. 90 Day Money Back
Guarantee on all items. Orders over $50. add 85C for insurance.

TRADEMARK OF DIGITAL RESEARCH.

NOT ASSOCIATED WITH DIGITAL RESEARCH OF CALIFORNIA, THE SUPPLIERS OF CPM SOFTWARE.

BLAK-RAY Ultraviolet
Intensity Meter

TWO MODELS:
LONG WAVE
AND

SHORTWAVE

Meter consists of a sensor cell attached to
a compact (3" x 3%" x 3") metering unit.
Can be hand held or placed directly on
surface for measuring. Can be used re-
motely, while connected to a meter hous-
ing by a 4- foot extension cord. Two
models available — one for long wave
and one for short wave ultraviolet. Read-
ings are in microwatts per square centi-
meter. Weight: 1 lb.

Completely assembled (includes sensor
cell, reduction screen, extension cord,
contrast filter and certification report.)

J-221 LONGWAVE
(300nm-400nm) $242. UU

J-225 SHORTWAVE _

(200nm-280nm) $2bU.OO

EPROM Erasing Lamp

• Erases 2708, 2716, 1702A, 5203Q, 5204Q, etc.

• Erases up to 4 chips within 20 minutes

• Maintains constant exposure distance of one inch

• Special conductive foam liner eliminates static
build-up

• Built-in safety lock to prevent UV exposure

• Compact - only 7-5/8" x 2-7/8" x 2"

• Complete with holding tray for 4 chips

UVS-11E $79.50

Jumbo 6-Digit Clock Kit

* Four .630”ht. and two .300”ht.
common anode displays

* Uses MMS314 clock chip

* Switches for hours, minutes and hold functions

* Hours easily viewable to 30 feet

* Simulated walnut case

* 115 VAC operation

* 12 or 24 hour operation

* Includes all components, case and wail transformer

* Size: 6*. x 3W x 141*

JE747 $29.95

• Bright .300 ht. comm, cath-
ode display

• Uses MM5314 clock chip
•Switches for hours, minutes

and hold modes

• Hrs. easily viewable to 20 ft.

• Simulated walnut case

• 1 1 5 V AC operation

• 12 or 24 hr. operation

• Incl. all components, case &
wall transformer

• Size: 654" x 3-1/8" x 134”

JE701

6-Digit Clock Kit $19.95

Regulated Power Supply

Uses LM309K. Heat sink .
provided. PC board con- — v
struction. Provides a solid
1 amp @ 5 volts. Can supply up
to ±5V, ±9V and ±12V with
JE205 Adapter. Includes compo-
nents, hardware and instructions.

Size: 3V»" x 5" x 2"H

JE200 $14.95

ADAPTER BOARD
-Adapts to JE200-
±5V, ±9V and ±12V

DC/DC converter with +5V input. Toriodal hi-
speed switching XMFR. Short circuit protection.
PC board construction. Piggy back to JE 200
board. Size. 3V*" x 2" x 9/1 6"H

\JE205

$12.95

MICROPROCESSOR COMPONENTS

— 8080A 8080A SUPPORT DEVICfS

8080A CPU S 7 95

8212 8-Bit Input/Output 3.25

8214 Priority Interrupt Control 5.95

8216 Bi Directional Bus Driver 3 49

8224 Clock Generator/Driver 3.96

8226 Bus Driver 3.49

8228 System Controller/Bus Driver 4 95

8238 System Controller 5.95

8251 Prog. Comm 1/0 (USART) 7.95

8253 Prog Interval rimer 14.95

8255 Prog Peripri 1/0 (PP1) 9 95

8257 Prog DMA Control 19 95

8259 Prog. Interrupt Control 14.95

6800/6800 SUPPORT DEVICES

MC6800 MPU $14.95

MC6802CP MPU with Clock and Ram 19.95

MC6810API 128X8 Static Ram 4.95

MC6821 Periph. Inter. Adapt (MC602O) 7.49

MC6828 Priority Interrupt Controller 10.95

MC6830L8 1024X8 Bit ROM (MC68A30-8) 14.95

MC6850 Asynchronous Comm. Adapter 6.95

MC6652 Synchronous Serial Data Adapt. 6.95

MC6660 0-600 bps Digital MODEM 10.95

MC6862 2400 bps Modulator 12.95

MC6880A Quad 3-State Bus Trans. (MC8T26) 2.25

MICROPROCESSOR CHIPS— MISCELLANEOUS

Z80(780C) CPU $13.95

Z8QA(780-1) CPU 15.96

COP1802 CPU 1995

2650 MPU 16.95

6502 CPU 11.95

8035N6 8-Bit MPU w/dock, RAM. 1/0 Imes 19 95
P8085 CPU 19.95

TMS9900JL 16-Bit MPU

49.95

-MICROPROCESSOR MANUALS -

M-Z80 User Manual
M-COP1802 User Manual
M-2650 User Manual

S7.50

7.50

5.00

2513(2140) Character Generator(upper case) $9 95
2513(3021) Character Generator(lower case) 9.95

2516 Character Generator 10.95

MM5230N 2048-Bit Read Only Memory 1.95

1101

1103

2101(8101)

2102

21L02

2111(8111)

2112

2114

2114L

2114-3

2114L-3

5101

5280/2107
7489
UP0414
(MK4027)
MM 5290-2

256X1

1024X1

256X4

1024X1

1024X1

256X4

256X4

1024X4

1024X4

1024X4

1024X4

256X4

4096X1

16X4

4K

16K

TMS4044 - 4K
45NL

TMS4045 1 024X4

2117 16.384X1

SHIFT REGISTERS -

Dual 25 Bit Dynamic
Dual 50 Bit Dynamic
Oual 100 Bit Static
Dual 64 Bit Accumulator
500/512 Bit Dynamic

MM500H
MM503H
MM506H
MM510H
MMS016H
2504(1404 A) 1024 Dynamic

MM5262

2 XXI

Static

Static

Static

Sialic

Static M0S

Static 450ns

Static 450ns low power

Sialic 300ns

Sialic 300ns low power

Static

Dynamic

Static

Dynamic 16 pin

Dynamic 16 pin 150NS
(UPD416/MK4116)
Static

Static

Dynamic 350ns
(house marked)

Dynamic

3.95
1.75

1.95

3.95

4.95

5.95

6.95
7.49

7.95

7.95

4.95
1.75
4.95

14.95

9.95

2518

2522

2524

2525

2527

2528

2529
2532
3341
74LS670

Hex 32 Bit Static
Dual 132 Bit Static
512 Bit Dynamic
1024 Dynamic
Dual 256 Bit Static
Oual 250 Sialic
Oual 240 Bit Static
Quad 80 Bit Static
fifo

4X4 Register File (TnState)

2.95
2.95
4.00
4.00
2.95
695
2 49

A-Y-5-1013 3CK BAUD

PROMS

1702A 2048 FAM0S

2716 16K‘ EPROM(lntel)

TMS2516 16K* EPROM (2716)

'Requires single -»-5V power supply
TMS2532 4KX8 EPROM

2708 8K EPROM

2716 T.l 16K" EPROM

'•Requires 3 voltages. — 5V. +5V, +12V
5203 2048 PROM

6301-1(7611) 1024
6330-1(7602) 256
82S23 32X8

BZS115 4096

82S 123(56 10) 32X8
74186 512

74188 256

74S287 1024

Open C Bipolar
Open Collector
Bipolar
Tristate

TTL Open Collector
TTL Open Collector

295

395

19.95

3.96

995

Function
Generator Kit

Provides 3 basic
waveforms: sine,

triangle and square
wave. Freq. range
from 1 HztolOOK
Hz. Output ampli-
tude from 0 volts
to over 6 volts
(peak to peak).
Uses a 12V supply
or a ±6V split sup-
ply. Includes chip,
P.C. Board, com-
ponents & instruc-
tions.

JE2206B $19.95

DIGITAL

THERMOMETER KIT

■ Dual sensors -control switch for indoor/
outdoor or dual monitoring— extension
up to 500 foot

■ Continuous LED .8" ht. display

■ Range: 40®F to 199®F / -40°Cto 100°C

■ Accuracy: ±1® nominal

■ Calibrate for Fahrenheit/Celsius reading

■ Sim. walnut case— AC wall adaptor Incl.

■ Size: 3K"H x 6-5/8"W x 1-3/8"D

JE300 $39.95

DESIGNERS’ SERIES
Blank Desk-Top Electronic Enclosures

• High strength epoxy molded
end pieces in mocha brown
finish.

• Sliding rear/bottom panel for
service and component ac-
cessibility.

• Top /bottom panels. 080 thk
alum. Alodine type 1200
finish (gold tint color) for
best paint adhesion after
modification.

• Vented top and bottom
panels for cooling efficiency.

• Rigid construction provides
unlimited applications.

The "DTE" Blank Desk Top Electronic Enclosuresare designed to blend and complement
today's modern computer equipment and can be used in both industrial and home. The
end pieces are precision molded with an internal slot (all around) to accept both top and
bottom panels. The panels are then fastened to 14" thick tabs inside the end pieces to
provide maximum rigidity to the enclosure. For ease of equipment servicing, the rear/
bottom panel slides back on slotted tracks while the rest of the enclosure remains in-
tact. Different panel widths may be used while maintaining a common profile outline.
The molded end pieces can also be painted to match any panel color scheme.

CONSTRUCTION:

Enclosure

Panel

Model No.

Width

PRICE

DTE-8

8.00”

$29.95

DTE-11

10.65”

$32.95

DTE-14

14.00”

$34.95

$10.00 Min. Order - U.S. Funds Only Spec Sheets - 254

Calif. Residents Add 6% Sales Tax 1981 Catalog Available - Send 414 stamp

Postage -Add 5% plus $1 Insurance (if desired)

PHONE
ORDERS
WELCOME
(415) 592-8097

MAIL ORDER ELECTRONICS - WORLDWIDE
1355 SHOREWAY ROAD, BELMONT, CA 94002
PRICES SUBJECT TO CHANGE

ameco

ELECTRONICS

2 National Semiconductor 1

w RAM SALE

MM5290J-2 (MK4i 16/UPD416) . . . $6.95 each

16K DYNAMIC RAM (150NS)

(8 EACH $49.95) (100 EACH $550.00/lot)

MM5298J-3A $3.25 each

8K DYNAMIC RAM (LOW HALF OF MM5290J) 200NS
(8 EACH $23.95) (100 EACH $250.00/lot)

MM2114-3 $5.95 each

4K STATIC RAM (300NS)

(8 EACH $43.95) (100 EACH $450.00/lot)

MM2114L-3 $6.25 each

4K STATIC RAM (LOW POWER 300NS)

(8 EACH $44.95) (100 EACH $4 75.00/lot)

Vacuum Vise

Vacuum-based light-duty
vise for small components
and assemblies. ABS con-
struction. 154" jaws, 154"
travel. Can be permanently
installed.

VV-1

$3.49

TRS-80

16K Conversion Kit

Expand your 4K TRS-80 System to 16K.

Kit comes complete with:

• 8 each MM5290-2 (UPD416) (16K Dynamic Rams)
150NS

* Documentation for conversion

TRS-16K $49.95

JE610 ASCII
Encoded Keyboard Kit

i-

The JE610 ASCII Keyboard Kit can be interfaced into
most any computer system. The kit comes complete
with an industrial grade keyboard switch assembly
(62-keys), IC's, sockets, connector, electronic compo-
nents and a double-sided printed wiring board. The
keyboard assembly requires +5V @ 150mA and —12V
@ 10mA for operation. Features: 60 keys generate the
126 characters, upper ana lower case ASCII set.
Fully buffered. Two user-define keys provided for
custom applications. Caps lock for upper-case-only
alpha characters. Utilizes a 2376 (40-pin) encoder
read-only memory chip. Outputs directly compatible
with TTL/DTL or MOS logic arrays. Easy interfacing
with a 16-pin dip or 18-pin edge connector.

JE610

(Case not included)

$79.95

Desk Top Enclosure for
JE610 ASCII Encoded Keyboard Kit

Compact desk-top enclosure: Color-coordinated de-
signer's case with light tan aluminum panels and molded
end pieces in mocha brown. Includes mounting hardware.
Size: 3K"H x 14%"W x 8%"D.

DTE-AK $49.95

SPECIAL: JE610/DTE-AK PURCHASED TOGETHER

(Value $129.90) $124.95

JE600

Hexadecimal Encoder Kit

FULL 8-BIT
LATCHED OUTPUT
19 KEY KEYBOARD

The JE600 Encoder Keyboard Kit provides two separate
hexadecimal digits produced from sequential key entries
to allow direct programming for 8-bit microprocessor
or 8-bit memory circuits. Three additional keys are
provided for user operations with one having a bistable
output available. The outputs are latched and monitored
with 9 LED readouts. Also included is a key entry strobe.
Features: Full 8-bit latched output for microprocessor
use. Three user-define keys with one being bistable
operation. Debounce circuit provided for all 19 keys.
9 LED readouts to verify entries. Easy interfacing with
standard 16-pin 1C connector. Only +5VDC required for
operation.

JE600

(Case not included)

$59.95

Desk-Top Enclosure for
JE600 Hexadecimal Keyboard Kit

Compact desk-top exclosure: Color-coordinated de-
signer’s case with light tan aluminum panels and molded
end pieces in mocha brown. Includes mounting hardware.
Size: 354"H x 8%"W x 8%"D.

DTE-HK . $44.95

SPECIAL: JE600/DTE-HK PURCHASED TOGETHER J
(Value $104.90) $99.95

228 Microcomputing, October 1980

C HP

SN7400N .25

SN7401N .20

SN7402N .25

SN7403N .25

SN7404N .25

SN7405N .25

SN7406N .35

SN7407N .35

SN7406N .25

SN7409N .25

SN7410N .25

SN7411N .25

SN7412N .35

SN7413N .40

SN7414N .85

SN7416N .29

SN7417N .29

SN7420N .20

SN7421N .29

SN7422N .39

SN7423N .25

SN7425N .29

SN7426N .29

SN7427N .25

SN7429N .39

SN7430N .25

SN7432N .25

SN7437N .25

SN7438N .40

SN7439N .25

SN7440N .20

SN7441N .89

SN7442N .59

SN7443N .75

SN7444N .75

SN7445N .75

SN7446N .79

SN7447N .69

SN7448N .79

SN74SON .20
SN7451N .20

SN7453N .20

SN74S4N .20
SN7459A .25

SN7460N .20

CD4000
CD4001
CD4002
C D4006
CD4007
CD4009
CD4010
CD4011
C 04012
CD4013
CD4014
CD4015
C 04016
CD4017
C 04018
C 04019
C 04020
CD4021
C 04022
C 04023
C 04024
C 04025
CD4026
CD4027

.39

1.19

1.39

1.19

74C00

74C02

74C04

74C08

74C10

74C14

74C20

74C30

74C42

74C48

74C73

74C74

■79

1.35

1.35

1.35

.49

7400 TTL

SN7470N
SN7472N
SN7473N
SN7474N
SN7475N
SN7476N
SN7479N 5.00

SN7480N .50

SN7482N .99

SN7483N .69

SN7485N .89

SN7486N .35

SN7489N 1.75

SN7490N .49

SN7491N .59

SN7492N .43

SN7493N .43

SN7494N .65

SN7495N .65

SN7496N .65

SN749/N 3.00

SN741CON 1.49
SN74107N .35

SN74109N .39

SN74116N 1.95
SN 74121 N .39
SN74122N .39

SN74123N .59

SN74125N .49

SN74126N .49

SN74132N .75

SN74136N .75

SN74141N .79

SN74142N 2.95
SN74143N 2.95
SN74144 N 2.95
SN74145N .79

SN74147N 1.95
SN74148N 1.29
SN74150N 1.25
SN74151N .59

SN74152N .59

SN74153N .79

SN74154N 1.25
SN74155N .79

SN741S6N .79
SN74157N .65

Hm

SN74160N .89

SN74161N .89

SN74162N .89

SN74163N .89

SN74164N .89

SN74165N .89

SN74166N 1.25
SN74167N 1.95
SN74170N 1.96
SN74172N 6.00
SN74173N 1.25
SN74174N .99

SN74175N .89

SN74176N .79

SN74177N .79

SN74179N 1.95
SN74180N .79

SN74181N 1.95
SN74182N .79

SN74184N 2.25
SN74185 N 2.25
SN74186N 9.95
SN74188N 3.95
SN74190N 1.25
SN74191N 1.25
SN74192N .89

SN74193N .89

SN74194N .89

SN74196N .69

SN74196N .89

SN74197N .89

SN74198N 1.49
SN74199N 1.49
SN74S200 4.95
SN74251N .99

SN74279N .79

SN74283N 2.25
SN74284 N 3.95
SN74285N 3.95
SN74365N .69

SN74366N .69

SN74367N .69

SN74368N .69

SN74390N 1.95
SN74393N 1.95

CMOS

C 04028
CD4029
CD4030
C D4035
CD4040
CD4041
CD4042
C 04043
CD4044
CD4046
CD4047
CD4048
C 04049
C 04050
C 04051
C 04053
CD4056
CD4059
C 04060
C D4066
C D4068
CD4069

1.79

2.50

1.35

1.19

1.19

2.95

9.95

C D4070
CD4071
C D4072
CD4076
C D4081
C 04062
CD4093
CD4098
MC 14409 14.95
MC14410 14.95
MC 14411 14.95
MC 14419 4.95

MC 14433 13.95
MC 14506 .75

MC 14507 .99

MC14562 11.95
MC 14583 2.49

CD4508
C D4510
CD4511
CD4515
C 04518
C D4520
C 04566

1.39

1.19

3.95

2.95

1.79

1.29

2.25

74C00

74C85

74C90

74C93

74C95

74C107

74C151

74C154

74C157

74C160

74C161

1.89

£46

3.95

2.25

1.69

1.69

74C163

74C164

74C173

74C192

74C193

74C195

74C922

74C923

74C92S

74C926

80C9S

80C97

1.69

1.59

1.39

1.69

1.69

1.59

5.49
5.75

7.50
7.50

.79

.79

78MG 1.75

LM106H .99
LM300H .80
LM301CN/H .35
LM302H 1.75
LM304H 1.49
LM306H .79
LM307CN/H .45
LM308CN/H 1.00
LM309H 1.10
LM309K 1.25
LM310CN 1.95
LM311N/H .90
LM312H 1.95
LM317K 3.95
LM318CN/H 1.95
LM319N 1.30
LM320K-5 1.35

LM320K-5.2 1.35
LM320K-12 1.25

LM320K-15 1.35

LM320K-18 1.35

LM320K-24 1.35

LM320T-5 1.25

LM320T-5.2 1.25
LM320T-8 1.25

LM320T-12 1.25

LM320T-15 1.25

LM320T-18 1.25

LM320T-24 1.25

LM323K-5 5.95

LM324N .99
LM339N .99
LM340K-5
LM340K-6
LM340K-8
LM340K-12 1.35
LM340K-15 1.35

LINEAR

LM340K-18 1.35

LM340K-24 1.35

LM340T-5
LM340T-6
LM340T-8
LM340T-12 1.25

LM340T-15 1.25

LM340T-18 1.25

LM340T-24 1.25

LM3S8N
LM370N
LM373N
LM377N
LM380N
LM380CN
LM381N
LM382N
NE510A
NE529A
NE531H/V 3.95
NE536T 6.00

1.25

1.25

1.25

1.00

1.95

3.25

2.96

1.25
.99

1.79

1.79

6.00

4.95

NE540
NE544N
NE550N
NE555V .39
NE556N .99
NE560 B 5.00
NE562B 5.00
LM565N/H 1.25
LM566CN 1.75
LM567V/H .99
NE570N 4.95
LM703CN/H .69
LM709N/H .29

6.00

4.95

1.30

LM710N .79
LM711N .39
LM723N/H .56
LM733N 1.00
LM739N 1.19
LM741CN/H .35
LM741-14N .39

LM747N/H .79
LM748N/H .59
LM1310N 1.95

LM1458CN/H .59
MC1488N 1.95

MC1489N 1.95

LM1496N .95

LM 1556V 1.75

MC1741SCP 3.00
LM2111N 1.95

LM2901N 1.95

LM3053N 1.50

LM3065N 1.49

LM3900N(3401).S9
LM3905N
LM3909N
MC5S58V
8038 B
LM754S0N
75451CN
75452CN
75453CN
75454CN
75491CN
75492CN
7S493N
75494CN
RC4136
RC4151
RC4194
RC4195

1.25

.59

4.95

1.25

1.25

1.25

3.95

4.95
4.49

L 11

V 11

74LS00
74LS01
74LS02
74LS03
74LS04
74LS06
74US08
74LS09
74LS10
74 LSI 1
74LS13
74LS14
74LS15
74LS20
74LS21
74LS22
74LS26
74LS27
74LS28
74LS30
74 LEM
74LS37
74LS40
74LS42
'4LS47

.35

74LS00TTL

74LS51
74LS54
74LS55
74LS73
74LS74
74LS75
74LS76
74LS78
74LS83
74LS85
74LS86
74LS90
74LS92
74LS93
74LS9S
74LS96
74LS107
74LS109
74L5112
74LS123
74LS125
74LS132
74LS136
74LS138

74LS139

74LS151

74LS155

74LS157

74LS160

74LS161

74LS162

74LS163

74LS164

74LS175

74LS181

74LS190

74LS191

74LS192

74LS193

74LS194

74LS195

74LS253

74LS2S7

74LS258

74L3200

74LS279

74LS367

74LS368

74LS670

JE6DS PROGRAMMER

2704/2708 EPROM PROGRAMMER

V Rtfintrt: 1 l E O f for Ho Key cntritt. 10 LEO l (2* 2* )

' 1 1 (0 s for Dell Memory Refiner. The Data Memory

- -» RAMi from (he (PROM Chip
• Onelopmenl tf truer oprotemr tyutimby mtani of a i

i and Bona) at any add rrn localien

EPROM ProfranniH coniistirg of:

A 10 hay Heaadtcimal Ktybnard atumhly. Pronramner Onard uumbly
4 pnwer urpplns and a LEO/Teit Socket Panel Board nuambly. The Ten
Sochet ii zero force inurtion type. Power rapuiremeeti: 11SVAC, S0H>. 6W.
■ Compact datk top enclosure: Color coordinated daifnar'i cast with Iqhl tan
panels and maided and paces in mocho brown. Sire: 1VH i U Tf « r“"“
Weipbt. 0 Ml

The JE608 EPROM Programmer is a completely tell contained unit which it independent of computer control and requires no additional
systems lor its operations The EPROM can bo programmed from the Hexadecimal Keyboard or Irom a pre programmed EPROM. The
JE608 Programmer can emulate a programmed EPROM by the use of tts internal RAM circuits. This will allow the user to test or pretest a
program, for a system, prior to programming a chip. Any changes in the program can be entered directly into the memory circuits with the
Hexadecimal Keyboard so that rewriting the entire program will not he necessary The JE608 Programmer contains a Programmet/Board
with 25 IC s and including power supplies of: -SV. *5V. *12V and +26V. The Hexadecimal Keyboard and LED/Tesi Socket Panel Board

JE608K KIT $399.95

JE608A Assembled and tested $499.95

XC556R .200” red 5/$l
XC556G .200” green 4/$l
XC556V .200” yellow 4/$l
XC556C .200” clear 4/$l
XC22R .200” red S/$l
XC22G .200” green 4/$l
XC22Y .200” yellow 4/$l
MV10B .170” red 4/SI

DISCRETE LEDS

MVSO .085” red 6/51
XC209R .125” red 5/$l
XC209G .125” green 4/$l
XC209Y .125” yellow 4/$l
XC526R .185” red 5/SI
XC526G .185” green 4/$l
XC526Y .185” yellow 4/$l
XC526C .185” clear 4/$l

XC111R .190” red 5/SI

XC111G .190” green 4/SI

XC111Y :190” yellow 4/$l

XC111C .190” clear 4/$l

INFRA-RED LED
V»”x ¥*”xl/16” flat
IRL-5/S1

C.A. — Common Anode DISPLAY LEDS C.C. — Common Cathode

Type
MAN 1
MAN 2
MAN 3
MAN 4
MAN 7G
MAN 7Y
MAN 72
MAN 74
MAN 82
MAN 84
MAN 3620
MAN 3630
MAN 3640
MAN 4610
MAN 4810
MAN 4840
MAN 6610
MAN 6630
MAN 6640
MAN 6650
MAN 6660
MAN 6710
MAN 6750
MAN 6760
MAN 6780
DL701
DL704

Polarity
C.A. — red
5x7 D.M.— red
C.C.— red
C.C.— red
C. A.— green
C. A.— yellow
C.A.— red
C.C. —red
C.A.— yellow
C.C.— yellow
C.A.— orange
C.A. —orange ± 1
C.C.— orange
C. A.— orange
C. A.— yellow
C.C.— yellow
C.A.— orange— DD
C. A.— orange ± 1
C.C.— orange— DD
C.C.— orange ± 1
C. A.— orange
C.A.— red— DD
C.C. — red i 1
C.A.— red
C.C.— red
C.A.— red ± 1
C.C.— red

Ht Price

.270 2.95
.300 4.95
.125 .25
.187 1.95
.300 1.25
.300 .99
.300 .75
.300 1.25
.300 .49
.300 .99
.300 .49
.300 .99
.300 .99
.300 .99
.400 .99

.560

.560

.560

.560

.560

.560

.560

.300

.300

Type

DL707

DL728

DL741

DL746

DL747

DL750

DL33B

FND70

FND358

FND359

FND503

FND507

5082-7730

5082-7613

5082-7620

5082-7623

5082-7730

5082-7731

5082-7750

5082-7751

5082-7760

5082-7300

5082-7302

5082-7304

5082-7340

Polarity
C.A. —red
C.C.— red
C.A.— red
C.A.— red ± 1
C.A. —red
C.C.— red
C.C. —red
C.C.

C.C. t 1
C.C.

C.C. (FND500)
C.A. (FND510)
C.A.— red

.300

.500

■m

.630

.600

.110
.250
.357
.357
.500
.500
.300
.800
.800

C.C., R.H.D.— red .300
C.A., L.H.D. — yel. .300
C.C., R.H.D.— yel. .300
C.A., L.H.D.— red .300
C.A., R.H.D.— red .300
C.A., L.H.D.— red .430
C.A., R.H.D.— red .430
C.C., R.H.D.— red .430
4x7 sgl. dig. RHDP .600
4x7 sgl. dig. LHDP .600
Overnge.char. (±1) .600
4x7 sgl. dig. hex. .600

1.25

1.25

19.95

19.95

15.00

22.50

RCA LINEAR

CA3013T 2.15

CA2023T 3.25

CA3035T 2.48

CA3039T 1.35

CA3046N 1.30

CA3059N 3.25

CA3060N 3.25

CA3080T 1.25

CA3081N 2.00

CA3082N 2.00

CA3083N 1.60

CA3086N .85

CA3089 N 3.75
CA3130T 1.39

CA3140T 1.25

CA3160T 1.25

CA3401N .59

CA3600N 3.50

CALCULATOR

CHIPS/DRIVERS

CLOCK CHIPS

MOTOROLA

MM572S

$2.95

MM5309

4.95

MC1408 L7

4.95

MM5738

2.95

MM5311

4.95

MC1408 L8

5.75

DM8864

2.00

MM5312

4.95

MC1439L

2.95

DM8865

1.00

MM5314

4.95

MC3022P

2.95

DM8887

.75

MM5316

6.95

MC3061P

3.50

DM8889

.75

MM5318

9.95

MC4016 (74416)7.50

9374 7-seg.

MM5369

2.95

MC4024P

3.95

LED driver

1.50

MM5377

4.95

MC4040P

6.95

MM 5309

4.95

MM5387/1998a 4.95

MC4044P

4.50

LOW PROFILE
(TIN) SOCKETS

-24 25-49 50-100

8 pin LP
14 pin LP
16 pin LP
18 pin LP
20 pin LP
22 pin LP
24 pin LP

36 pin LP
40 pin LP

.60

.63

.59

.62

.58

.61

ff

Ifllllf 1

8 pin WW
10 pin WW
14 pin WW

SOLDERTAIL (GOLD)
STANDARD

1-24 25-49 50-100

8 pin SG

.39

.35

.31

16 pin WW

14 pin SG

.49

.45

.41

18 pin WW

16 pin SG

.54

.49

.44

20 pin WW

18 pin SG

.59

.53

.48

22 pin WW

24 pin SG

.79

.75

.69

24 pin WW

28 pin SG

1.10

1.00

.90

28 pin WW

36 pin SG

1.65

1.40

1.26

36 pin WW

40 pin SG

1.75

1.59

1.45

40 pin WW

IK

TrrrTrr

SOLDERTAIL
STANDARD (TIN)

14 pin ST
16 pin ST
18 pin ST
24 pin ST
28 pin ST
36 pin ST
40 pin ST

1. IS
1.30

WIRE WRAP SOCKETS
(GOLD) LEVEL #3

1-24 2S-49 50-100

.59

M

.54

.63

1.35

1.26

1.53

1.99

2.09

1.23

1.14

1.38

1.79

1/4 WATT RESISTOR ASSORTMENTS -5%

ASST. 2
ASST. 3

10 OHM 12 OHM 15 OHM 18 OHM 22 OHM

27 OHM 33 OHM 39 OHM 47 OHM 56 OHM

68 OHM 82 OHM 1 00 OHM 120 OHM 150 OHM

180 OHM 220 OHM 270 OHM 330 OHM 390 OHM

470 OHM 560 OHM 680 OHM 820 OHM IK
2.2K

1.2K

3.3K

8.2K

3.9K

4.7K

I2K

I50K
Sta. 390H

5.6k

1SK

39K

100K

270K

680K

2.7K

6.8K

18K

47K

I20K

330k

820K

ASST. 8R Includes Resistor Assortments 1-7 (350 PCS.) $10.95ea.

50 PCS

$1.95

50 PCS

$1.95

50 PCS

$1.95

50 PCS

$1.95

50 PCS

$1.95

50 PCS

$1.95

50 PCS

$1.95

$10.95 ea.

$10.00 Min. Order — U.S. Funds Only Spec Sheets — 254

Calif. Residents Add 6% Sales Tax 1981 Catalog Available - Send 414 stamp

Postage — Add 5% plusSI Insurance (if desired)

PHONE
ORDERS
WELCOME
(415) 592-8097

MAIL ORDER ELECTRONICS - WORLDWIDE

1355 SHOREWAY ROAD, BELMONT, CA 94002 ^41

PRICES SUBJECT TO CHANGE

J lameco

l ijuui.i.iTCn

AY-5-9100

AY-5-9200

AY-5-9500

AY -5-2376

HD0165

74C922

74C923

TELEPHONE/KEYBOARD CHIPS

Push Button Telephone Dialler
Repertory Dialler
CMOS Clock Generator
Keyboard Encoder (88 keys)
Keyboard Encoder (16 keys)
Keyboard Encoder (16 keys)
Keyboard Encoder (20 keys)

.A

4.95

$14...

14.95

4.95

11.95

7.95
5.49
5.75

ICM7045

ICM7205

ICM7207

ICM7208

ICM7209

ICM CHIPS

CMOS Precision Timer
CMOS LED Stop watch /Timer
Oscillator Controller
Seven Decade Counter
Clock Generator

24.95

19.95
7.50
19.95

6.95

NM0S READ ONLY MEMORIES

MCM6571 128 X 9 X 7 ASCII Shifted with Greek 13.50

MCM6574 128 X 9 X 7 Math Symbol & Pictures 13.50

MCM6575 128 X 9 X 7 Alpha Control Char Gen 13.50

MISCELLANEOUS

TL074CN Quad Low Noise bi-fet Op Amp

TL494CN Switching Regulator

TL496CP Single Switching Regulator

11C90 Divide 10/11 Prescaler

95H90 Hi-Speed Divide 10/11 Prescaler

4N33 Photo-Darlington Opto-lsolator

MK50240 Top Octave Freq. Generator

DS0026CH 5Mhz 2-phase MOS clock driver

TIL308 . 27" red num. display w/integ. logic chip 10.95

MM5320 TV Camera Sync. Generator 14.95

MM5330 4tt Digit DPM Logic Block (Special) 3.95

LD110/111 3Vi Digit A/D Converter Set 25.00/set

MC14433P Digit A/D Converter 13.95

2.49

4.49

1.75

14.95

11.95

1.25

17.50

3.75

LITR0NIX ISO-LIT 1

Photo Transistor Opto-lsolator
(Same as MCT 2 or 4N25)

49 i eacli

SN 76477

SOUND GENERATOR
Generates Complex Sounds
Low Power - Programmable

$3.95 each

TV GAME CHIP AND CRYSTAL

AY-3-8500-1 and 2.01 MHZ Crystal (Chip & Crystal _ n _ . .

includes score display. 6 games and select angles, etc. f.jQ/ SCI

XR205 $8.40

XR210 4.40

XR215 4.40

XR320 1.55

XR-L555 1.50

XR555 .39

XR556 99

XR567CP 99
XR567CT 1.25
XR1310P 1.95

XR1468CN 3.85
XR1488 1.95

XR1489 1.95

EXAR

JE2206K9 19.95
XR1800 3.20

XR2206 4.40

XR2207 3.85

XR2208 5.20

XR2209 1.75

XR2211 5.25

XR2212 4.35

XR2240 3.45

XR2242CP

XR2264

XR2556

XR2567

XR3403

XR4136

XR4151

XR4194

XR4202

XR4212

XR4558

XR4739

XR4741

1 1.50

4.25
3.20
2.99

1.25
1.25
3.95
1.45
3.60
2.05

.75

1.15

1.47

nmnFS

TYPE

VOLTS W

PRICE

1N4002

100 PIV 1 AMP

12/1.00

TYPE

VOLTS W

PRICE

1N4003

200 PIV 1 AMP

12/1.00

1N746

33

400m

4/1.00

1N4004

400 PIV 1 AMP

12/1 00

1N751

5 1

400m

4/1.00

1N40O5

600 PIV 1 AMP

10/1 00

1N752

5.6

400m

4/1 00

1NA006

800 PIV 1 AMP

10/1.00

1N753

6.2

400m

4/1.00

1N4007

1000 PIV 1 AMP

10/1.00

1N754

6.8

400m

4/1.00

1N3600

50 200m

6/1.00

1N757

80

400m

4/1.00

1N4148

75 10m

15/1 00

1N759

120

400m

4/1.00

1N4154

35 10m

12/1.00

1N959

8.2

400m

4/1 00

1N4733

5.1 1w

4/1.00

1N965

IS

400m

4/1.00

1N4734

5.6 1w

4/1.00

1N5232

56

500m

4/1.00

1N4735

6 2 1w

4/1.00

1N5234

6.2

500m

4/1.00

1N4736

68 1w

4/1.00

1N5235

6.8

500m

4/1.00

1N4738

8.2 1w

4/1.00

1N5236

7.5

500m

4/1.00

1N4742

12 1w

4/1.00

1N5242

12

500m

4/1.00

1N4744

15 1w

4/1.00

1N5245

15

500m

4/1.00

INI 183

50 PIV 35 AMP

1.60

1N456

25

40m

6/1 00

IN1 1 84

100 PIV 35 AMP

1.70

1N458

150

7m

6/1.00

INI 185

150 PIV 35 AMP

1.70

1N485A

180

10m

5/1.00

INI 186

200 PIV 35 AMP

1 80

1N4001

50 PIV 1 AMP

12/1.00

INI 188

400 PIV 35 AMP

3.00

SCR AND FW BRIDGE RECTIFIERS

C36D
C36M
C106B1
2N2328
MDA 980-1
MDA 980-3

15A @
35A @
3.6 A @
1.6A @
12A @
12A @

400V

600V

200V

300V

50V

200V

SCR(2N1849)

SCR

SCR

SCR

FW Bridge Rec.
FW Bridge Rec.

$1.95

2.25

.50

.50

1.95

2.25

TRANSISTORS

2N3904

4/1.00

MPSA05

3/1.00

2N3055

.89

2N3905

4/1.00

MPSA06

3/1.00

MJE3055

1.00

2N3906

4/1.00

TIS97

4/1.00

2N3392

4/1.00

2N4013

.65

TIS98

4/1.00

2N3398

4/1.00

2N4123

4/1.00

40409

1.75

PN3567

3/1.00

PN4249

4/1.00

40410

1.75

PN3568

4/1.00

PN4250

4/1.00

40673

1-75

PN3569

4/1.00

2N4400

4/1.00

2N918

2/1.00

MPS3638A

4/1.00

2N4401

4/1.00

2N2219A

2/1.00

MPS3702

4/1.00

2N4402

4/1.00

2N2221A

3/1.00

2N3704

4/1.00

2N4403

4/1.00

2N2222A

3/1.00

MPS3704

4/1.00

2N4409

4/1.00

PN2222 Plastic

6/1.00

2N3705

4/1.00

2N5Q86

4/1.00

2N2369A

2/1.00

MPS3705

4/1.00

2N5087

4/1.00

MPS2369

4/1.00

2N3706

4/1.00

2N5088

4/1.00

2N2484

4/1.00

MPS3706

4/1.00

2N5CS9

4/1.00

2N2906

2/1.00

2N3707

4/1.00

2N5129

4/1.00

2N2907

3/1.00

2N3711

4/1.00

PN5134

4/1.00

2N2925

4/1.00

2N3724A

.65

PN5138

4/1.00

MJE2955

1.25

2N3725A

1.00

2N5139

4/1.00

2N3053

2/1.00

2N3772

2.25

2NS210

4/1.00

2N3823

1.00

2N5449

3/1.00

2N3903

4/1.00

2N5951

2400

CAPACITOR

CORNER

10 pf

M

.06

.05

ooi m f

a

Tr

.05

22 pf

M

jH

M

0047fiF

.08

M

Jt 6

47 pi

■ US

jfi

.05

OVF

.08

M

.a

100 pi

.06

.06

.05

.022/tF

JB

xn

06

220 pi

.08

.06

.05

047uF

.06

.06

470 of

.08 .06 . 06 i u F

100 VOLT MYLAR FILM CAPACITORS

.15

.12

.10

001ml

12

10

.07

022ml

.13

.11

08

0022

12

10

.07

047ml

.21

.17

13

0047ml

12

10

07

Imf

.27

23

.17

Olmf

12

.10

07

,22ml

33

.27

22

. 1 /35V
15/35V
22/35V
33/35V
.4 7/35 V
.68 /35V
1.0/35V

.47/50 V

1.0/50V

3 3: 50V

4.7/25V

10/25V

10/50V

22/25V

22/50V

47/25V

47/50V

100/25V

100/50V

220/25V

220/50V

470/25 V

1000/I6V

2200/1 6 V

+ 20*. DIPPED TANTALUMS (SOLID) CAPACITORS

.39 .34 .29 1.5/35V .41 .37

.39 .34 .29 2. 2/35 V 41 .45

.39 .34 .29 3.3/25V .53 .47

.39 .34 .29 4.7725V .63 .56

.39 .34 .29 6.8/25 V .79 .69

■S *2i *2 T5/2SV l-M i.a

.39 . 34 .29 22/6V -79 -69

.19 .16 .12
.17 .15 .11
.18 .15 .11
.18 .15 .11
.19 .16 .12

.41 .37 .34

.79 .69 .61

47/25V
47/50V
10/16V
1 0/25V
1.0/50V
47/16V
47/25V
4 7 /50V
10/16V
10/25V
10/50V
47/SOV
100/ 16V
10O/25V
100/50V
220/16V
470/25 V

.15 .13 .12

.16 .14 .13

.16 .14 .13

.17 .15 .14

.17 .15 .14
.15 .13 .12
.16 .14 .13

t/ 0 Reader Service index— page 241

Microcomputing , October 1980 229

MK ITATIC RAID

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195

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©

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• NO TECHNICAL BACKGROUND ASSUMED-

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CONCORD

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componems

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hold input* Olher lunctwn* include IPH pi
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The MSMS43P normal ope a-e* horn a 5 -on

230 Microcomputing, October 1980

Start learning and computing for only $129. 95 with a Netronics 8085-based
computer kit. Then expand it in low-cost steps to a business/development system
with 64k or more RAM, 8" floppy disk drives, hard disks and multi- terminal HO.

THE NEW EXPLORER/85 SYSTEM

Special! Full 8" floppy, 64k system for less than the price of a mini! Only $1499.95!

Imagine — for only $129.95 you can own the starting
level of Explorer/85, a computer that’s expandable into
full business/development capabilities — a computer
that can be your beginner system, an OEM controller,
or an IBM-formatted 8" disk small business system.
From the first day you own Explorer/85, you begin
computing on a significant level, and applying princi-
ples discussed in leading computer magazines. Ex-
plorer/85 features the advanced Intel 8085 cpu, which
is 100% compatible with the older 8080A. It offers on-
board S-100 bus expansion. Microsoft BASIC in ROM,
plus instant conversion to mass storage disk memory
with standard IBM-formatted 8" disks. All for only
$129.95. plus the cost of power supply, keyboard/
terminal and RF modulator if you don’t have them (see
our remarkable prices below for these and other, ac-
cessories). With a Hex Keypad/display front panel.
Level “A" can be programmed with no need for a ter-
minal. ideal for a controller. OEM, or a real low-cost
start.

Level “A” is a
complete operating
system, perfect for
beginners, hobbyists,
industrial controller
use. $129.95

LEVEL “A” SPECIFICATIONS

Explorer/85's Level ’A” system features the advanced
Intel 8085 cpu, an 8355 ROM with 2k deluxe monitor/
operating system, and an advanced 8155 RAM I/O . . .
all on a single motherboard with room for RAM/ROM/
PROM/ EPROM and S-100 expansion, plus generous
prototyping space.

PC Board: Glass epoxy, plated through holes with
solder mask. • I/O: Provisions for 25-pin (DB25) con-
nector for terminal serial I/O. which can also support a
paper tape reader . . . cassette tape recorder input and
output . . . cassette tape control output . . . LED output
indicator on SOD (serial output) line . . . printer inter-
face (less drivers) . . . total of four 8-bit plus one 6-bit
I/O ports. • Crystal Frequency: 6.144 MHz. • Control
Switches: Reset and user (RST 7.5) interrupt . . . addi-
tional provisions for RST 5.5, 6.5 and TRAP interrupts
onboard. • Counter/Timer Programmable, 14-bit bi-
nary. • System RAM: 256 bytes located at F800. ideal
for smaller systems and for use as an isolated stack
area in expanded systems . . . RAM expandable to 64K
via S-100 bus or 4k on motherboard.

System Monitor (Terminal Version): 2k bytes of
deluxe system monitor ROM located at F000. leaving
free for user RAM/ ROM. Features include tape
load with labeling . . . examine/change contents of
memory . . . insert data . . . warm start . . . examine and
change all registers . . . single step with register display
at each break point, a debugging/traininc feature ... go
to execution address . . . move blocks of memory from
one location to another . . . fill blocks of memory with a
constant . . . display blocks of. memory . . . automatic
baud rate selection to 9600 baud . . . variable display
line length control (1-255 characters/line) . . . chan-
nelized I/O monitor routine with 8-bit parallel output
for high-speed printer . . . serial console in and console
out channel so that monitor can communicate with I/O
ports.

System Monitor (Hex Keypad/Display Version):
Tape load with labeling . . . tape dump with labeling
. . . examine/change contents of memory . . . insert data
. . . warm start . . . examine and change all registers . . .

(Also available wired & tested. $1799.95)

Full 8” disk system for less than the price of a mini (shown with
Nctronics Explorer/85 computer and new terminal). System features
floppy drive from Control Data Corp., world’s largest maker of
memory storage systems ( not a hobby brand/)

single step with register display at each break point . . .
go to execution address. Level *'A" in this version
makes a perfect controller for industrial applications,
and is programmed using the Netronics Hex Keypad/
Display. It is low cost, perfect for beginners.

HEX KEYPAD/DISPLAY SPECIFICATIONS
Calculator type keypad with 24 system-defined and 16
user-defined keys. Six digit calculator-type display,
that displays full address plus data as well as register
and status information.

LEVEL ”B” SPECIFICATIONS
Level ”B" provides the S-100 signals plus buffers/
drivers to support up to six S-100 bus boards, and in-
cludes: address decoding for onboard 4k RAM expan-
sion selectable in 4k blocks . . . address decoding for
onboard 8k EPROM expansion selectable in 8k blocks
. . . address and data bus drivers for onboard expansion
. . . wait state generator (jumper selectable), to allow the
use of slower memories . . . two separate 5 volt regula-
tors.

LEVEL “C” SPECIFICATIONS

Level “C” expands Explorer/85’s motherboard with a
card cage, allowing you to plug up to six S-100 cards
directly into the motherboard. Both cage and card are
neatly contained inside Explorer’s deluxe steel
cabinet. Level ”C" includes a sheet metal superstruc-
ture. a 5-card, gold plated S-100 extension PC board
that plugs into the motherboard. Just add required
number of S-100 connectors.

Explorer/85
With Level "C”
Card Cage.

LEVEL “D” SPECIFICATIONS

Level ”D” provides 4k of RAM, power supply regula-
tion. filtering decoupling components and sockets to
expand your Explorer/85 memory to 4k (plus the origi-

nal 256 bytes located in the 8155A). The static RAM
can be located anywhere from to EFFF in 4k
blocks.

LEVEL “E” SPECIFICATIONS

Level “E” adds sockets for 8k of EPROM to use the
popular Intel 2716 or the TI 2516. It includes all sockets,
power supply regulator, heat sink, filtering and decou-
pling components. Sockets may also be used for 2k x 8
RAM IC’s (allowing for up to 12k of onboard RAM).
DISK DRIVE SPECIFICATIONS

• 8" CONTROL DATA CORP. • Data capacity: 401.016 bytes

(SD). 802.032 bytes (DD).
unformatted.

• Access time; 25ms (one
track).

professional drive.

• LSI controller.

• Write protect.

• Single or double density.

DISK CONTROLLER/ I/O BOARD
SPECIFICATIONS

• Controls up to four 8" drives.

• 1771 A LSI (SD) floppy disk
controller.

• Onboard data separator
(IBM compatible).

• 2 Serial I/O ports

• Autoboot to disk system
when system reset.

2716 PROM socket included
for use in custom
applications.

Onboard crystal controlled.
Onboard I/O baud rate
generators to 9600 baud.
Double-sided PC board
(glass epoxy.)

DISK DRIVE CABINET/POWER SUPPLY

• Deluxe steel cabinet with individual power supply for max-
imum reliability and stability.

ORDER A COORDINATED
EXPLORER/85 APPLICATIONS
PAR!

Beginner’s Pak (Save $26.00!) — Buy Level "A” (Ter-
minal Version) with Monitor Source Listing and AP-1
5-amp Power Supply: (regular price $199.95), now at
SPECIAL PRICE: $169.95 plus post. & insur.
Experimenter’s Pak II (Save $53.40!) — Buy Level
“A" (Hex Keypad/Display Version) with Hex
Keypad/Display. Intel 8085 User Manual, Level "A”
Hex Monitor Source Listing, and AP-1 5-amp Power
Supply: (regular price $279.35). all at SPECIAL
PRICE: $219.95 plus post. & insur.

Special Microsoft BASIC Pak (Save $103.00!) — In-
cludes Level ’’A” (Terminal Version). Level “B".
Level "D" (4k RAM). Level “E”. 8k Microsoft in
ROM. Intel 8085 User Manual. Level "A" Monitor
Source Listing, and AP-1 5-amp Power Supply: (regu-
lar price $439.70), now yours at SPECIAL PRICE:
$329.95 plus post. & insur.

ADD A TERMINAL WITH CABINET,
GET A FREE RF MODULATOR: Save
over $114 at this SPECIAL PRICE: $499.95
plus post. & insur.

Special 8" Disk Edition Explorer/85 (Save over $104!)

— Includes disk-version Level ’’A”. Level ’’B’’. two
S-100 connectors and brackets, disk controller, 64k
RAM, AP-1 5-amp power supply, Explorer/85 deluxe
steel cabinet, cabinet fan, 8" SD/DD disk drive from
famous CONTROL DATA CORP. (not a hobby
brand!), drive cabinet with power supply, and drive
cable set-up for two drives. This package includes
everything but terminal and printers (see coupon for
them). Regular price $1630.30. all yours in kit at
SPECIAL PRICE: $1499.95 plus post. & insur. Wired
and tested, only $1799.95.

Special! Complete Business Software Pak (Save
$625.00!) — Includes CP/M 2.0. Microsoft BASIC.
General Ledger. Accounts Receivable. Accounts
Payable. Payroll Package: (regular price $1325). yours
now at SPECIAL PRICE: $699.95.

Dept. K10 Please send the items checked below:

□ Explorer 85 Level “A” Idt (Terminal Version). . $129.95 plus
$3 post. & insur.

□ Explorer/85 Level M A” Idt ( Hex Keypad/Display Version) . .
$129.95 plus $3 post. & insur.

□ 8k Microsoft BASIC on cassette tape S64.95 postpaid.

C 8k Microsoft BASIC in ROM kit (requires Levels ”B ”. “D” and
"E") . $99.95 plus $2 post. & insur.

□ Level “B" (S- 100) kit $49.95 plus $2 post. & insur.

□ Level “C” (S-100 6-card expander) kit $39.95 plus $2 post.
& insur.

□ Level "IT (4k RAM) Idt $69.95 plus S2 post. & insur.

□ Level “E” (EPROM/ ROM) kit $5.95 plus 50C p&h.

□ Deluxe Steel Cabinet for Explorer/85 $49.95 plus $3 post.
& insur.

□ Fan For Cabinet . . $15.00 plus $1.50 post. & insur

□ ASCII Keyboard/ Computer Terminal Idt: features a full 128

character set. u&l case: full cursor control: 75 ohm video
output: convertible to baudot output: selectable baud rate.
RS232-C or 20 ma. I/O. 32 or 64 character by 16 line formats,
and can be used with either a CRT monitor or a TV set (if you
have an RF modulator) . SI49.95 plus $3.00 post. & insur.

□ DeLuxe Steel Cabinet for ASCII keyboard/terminal . .
$19.95 plus $2.50 post. & insur.

□ New! Terminal/ Monitor: (See photo) Same features as above,
except 12" monitor with keyboard and terminal is in deluxe
single cabinet: kit $399.95 plus $7 post. & insur.

□ Hazeltine terminals: Our prices t<xi low to quote — CALL US
C Lear-SIgler terminals/printers: Our prices i<kj low to quote:

CALL US

□ Hex Keypad/ Display Idt $69.95 plus $2 post. & insur.

□ AP-1 Power Supply Kit ±8V @5 amps) in deluxe steel cabinet

$39.95 plus $2 post & insur.

□ Gold Plated S- 100 Bus Connectors $4.85 each, postpaid

□ RF Modulator kit (allows you to use your TV set as a monitor)
...$895 postpaid.

□ 16k RAM Idt (S-100 board expands to 64k) $199.95 plus $2

post. & insur.

□ 32k RAM Idt $299.95 plus $2 post. & insur.

□ 48k RAM kit $399.95 plus $2 post. & insur

□ 64k RAM Idt $499.95 plus $2 post. & insur

□ 16k RAM Expansion Idt (to expand any of the above in 16k

blocks up to 64k) . $99.95 plus $2 post. & insur. each.

□ Intel 8085 cpu Users’ Manual $7.50 postpaid

□ 12" Video Monitor (10MHz bandwidth) . $139.95 plus $5

post. & insur.

□ Beginner’s Pak (see above) $169.95 plus $4 post. & insur.

□ Experimenter’s Pak (see above) . . $219.95 plus $6 post. &
insur.

□ Special Microsoft BASIC Pak Without Terminal (see above) .
$329.95 plus $7 post. & insur

□ Same as above, plus ASCII Keyboard Terminal With Cabinet,

Get Free RF Modulator (see above) . $499.95 plus $10 post.

& insur.

□ Special 8" Disk Edition Explorer/85 (see above) . $1496.95

plus $26 post. & insur.

□ Wired & Tfested SI 799.95 plus $26 post. & insur.

□ Extra 8" CDC Floppy Drives $499.95 plus $12 post & iasur.
U Cabinet & Power Supply For Drive $69.95 plus $3 post. ft

insur.

□ Drive Cable Set-up For TWo Drives $25 plus $1.50 post. &
insur.

H Disk Controller Board With 1/0 Ports $199.95 plus $2 post.

& insur.

Cl Special: Complete Business Software Pak (see above)
$699.96 postpaid.

SOLD SEPARATELY:

□ CP/M 1.4 $100 postpaid.

□ CP/M 2.0 $l50poslpaid.

□ Microsoft BASIC $325 postpaid.

□ Intel 8065 cpu User Manual $7 .50 postpaid.

□ Level “A” Monitor Source Listing $25 postpaid.

Continental U.S.A. Credit Card Buyers Outside Connecticut

CALL TOLL FREE: 800-243-7428 m

To Order From Connecticut Or For Technical

Assistance, call (203) 354-9375 ~

Total Enclosed (Conn res. add sales lax) $

Paid By:

D Personal Check □ Cashier's Check/Money Order

□ VISA □ Master Charge (Bank No )

Acct. No. Exp. Date

Signature

Print

Name

Address

City

State Zip

NETRONICS Research & Development Ltd.
ISA 333 Litchfield Road, New Milford, CT 06776

iS Reader Service index — page 241

Microcomputing, October 1980 231

HOBBY WORLD

ELECTRONICS, INC.

Call Toll-Free: USA (800) 423-5387 in California: (800) 382-3651

Local & Outside USA: (213) 886-9200

EMAKO 22 BM

fes y

1

MICROPRINTER H\r\

A dependable, low cost addition to B |

wrvur rnmnutor cuctom fpatnrinn a T v.V-'-ll i

PI 1

9x7 dot matrix character format, bi- /

directional printing at 125 CPS, and
sprocket feed paper mechanism. Line i
length is selectable at 40, 80. or 132 1

Mt

loaded from the bottom or rear. vf ,

/

asynchronous serial interfacing. cat No. Description Price

wt 22 lbs. 2455 Parallel interface $834.75

2456 RS-232C Serial interface $894.00

SSM OBI

vector Jump &

Prototyping
Card

Plug compatible for s-100 bus
systems, features full 16 bit vector
jump address with dip selection of
8080 or Z80. Can be set to jump on
Power-on-clear, reset, or both. cat No 1429 OBI kit $41.95

Prototyping areas on the card for ten cat No 1430 OBI A&T $67.95

16-pin ICs, three 24-28 pin ICs, and cat No. 1431 OBI bareboard $24.95
two spare regulator patterns.

SSM CB1-A

8080 CPU Board

Just add an I/O board and it’s a computer! 256
bytes of on board RAM, with option for 2K of on
board PROM, includes a power-on, preset jump
circuit, and mwrite is available, allowing use
without a front panel. There’s a parallel input
port with status, and AlP controlled addressing:
or PROM in 2K blocks increments; RAM in 256
byte increments; input port for addresses 0-31 in
decimal. <iiC75 l/if

Cat NO. 1403 CBI-AKIt ? ■ >9 IVI V
Cat NO. 1 441 cbi -A Bareboard $27.95

CCS 32K static
RAM Board

uses 2114, 250ns fully static ram s,
Bank selectable in 8K blocks.
Enable/Disable on power up or Reset.
Compatible with North Star, Alpha
Micro, Cromeco, etc. Also front panel
compatible, addressable in 8K blocks.
Selectable wait state, wt. 1 lb.

Cat NO. 2644 A&T

$649

CCS

Z-80 CPU Boai

An all new z-80 CPU board loaded with such
great features as S-100/Altair/Imsai compatibility,
Power-on jump to any Memory address,
selectable z-80 monitor ROM, selectable Mi wait
states, full handshake, auto band (2 baud-56K
baud) selection, selectable port address, separate
baud rate oscillator and on board RS-232 100%
disable option serial port. This board also boasts
front panel support compatiblity, Z-80 NMI
capability, phantom line capability, z-80 interrupt
capability and status valid on Data Lines during
psnc. wt. 3 lbs. PMA

Cat No. 2646

CCS 2422

Disk Controller

This disk controller is equipped with a soft sector
format, will support single and double density
formats, and supports up to four SV*" and/or 8”
single or double sided drives, it has ROM
controlled addressing for I/O mapped and/or
(optional) memory mapped operation, fastseek
capability for voice-coil type drive, adjustable
write precompensation, digital phase-locked
data separator, selectable auto-wait on Data or
Control port and on-board 2K Byte
Boot/program ROM (2716K A copy of CP/M 2.2 is
included,
cat NO. 2645

CCS

64K Dynamic
RAM Board

Uses low power 4116 Dynamic RAM’s,
Bank selectable in 16K blocks, bank
Enable/ Disable on power-up or reset,
"fail safe" modes for transparent
refresh on 8080 or Z-80, 4mhz
operation, phantom line capability
and compatible with front panel
systems.

Wt. 12 oz.
cat NO. 2647 A&T

SSM AIO

Apple II Serial &
Parallel interface

Allows maximum flexibility for interfacing Apple
II with peripherals (printers, plotters, terminals,
modems, etc.) Communicates with both serial
and parallel devices, and can interface with both
at the same time. Complete with software and
firmware for serial and parallel communications.

• Features one

RS232 serial interface with:

Three handshaking lines (RTS, CTS, DCD); Nine
standard baud rates from 110 to 19,200 baud,
including 134.5 baud for selectrics; additional
baud selectable through external input; baud
rates rotary switch selectable, no jumpers
required; serial communication modes software
controlled.

• Two bi-directional
8-bit parallel ports with:

Four additional interrupt and handshaking lines;
interface configuration software controlled,
includes on-board firmware for controlling serial
interface and software for driving parallel
printers. Firmware for parallel interface control
optional. Serial and parallel interface cable
assemblies included, includes comprehensive
manual and application notes.

cat NO. 1918 AIO Kit $1 35.00

cat NO. 1919 AIO A&T $175.00

SSM MB6B

8K Static RAM Board

{gast ksoJ bun^l

~\lniiiiiinnnunii

iiirnSrftll™

8K bytes by 8 bits, fully buffered, compatible
with 8080, 8085 and Z80. Dip switch addressing of
independent 4K halves lets the MB6B think like
two 4K boards, or one 8K board, independent 4K
addressing allows the flexibility to meet varying
software memory needs, uses low power 21L02
ram s, operates at 2 or 4MHZ, and is compatible
with direct memory access controllers.

cat no.

*1400- A
•1400-B
1401 -A
1401-B
*1402

Description
450ns kit
250ns kit
450ns A&T
250ns A&T
Bareboard

Price
$131.75
§143.95
§182.50
§195.00
§ 22.50

PROGRAMMA

Data Base
Management 5

An easy method of creating data files
and storing them in disk memory for
future use. Allows you to store and
manipulate data for maximum
productivity, and modify or
incorporate your own routines. Uses
Radio Shack's TRSDOS/ BASIC language,
cat NO. 2146

TRS-80L2, 16K >49

PROGRAMMA

SUPER

STARWARS

You have just come out of
hyperspace to find you are right in
front of a squadron of imperial
fighters --- and your only hope for
survival is to destroy them before
they get you! You will be attacked by
32 fighters as they close in on

you good luck. Aip 95

cat NO. 2130 913

Apple, 32K Cassette, integer

MICROSOFT

TRS-80

Level III BASIC

Loads with SYSTEM command, yet has
the power of a hardware
modification. Offers easier loading,
keyboard debounce, BASIC access to
RS232, new commands, and easier,
more powerful graphics. Eliminates
volumn sensitivity when loading
cassettes, shorthand programming
commands, and long error messages,
cat no. 1332

TRS-80 L2, 16K, Cassette 949

5 %" Diskettes

VERBATIM 525 SERIES

__ . Single sided • Double Density

perfect for commercial and general applications.

Description
Soft sector
10 hole, hard
16 hole, hard

Type

525-01

525-10

525-16

use for
trs- 80, etc.

North star, Apple
Micropolls, etc.

Cat No

2330

2331

2332

VERBATIM 577 SERIES

• certified twice, 77 tracks

• Single sided, double density

• Built-in hub protector ring

• For critical data applications

Description Type Use for

Soft sector 577-01 TRS-80

10 hole, hard 577-10 North Star, Apple

16 hole, hard 577-16 Micropolls, etc.

TRS-80 and APPLE

16K Memory
Add-on

Everything you need to upgrade your
system! includes 4 pages of illustrated
instructions. Complete with RAM's
and preprogrammed jumpers. No
special tools required! wt. 4 oz.

Cat No Description
1 1 56 For TRS-80 Keyboard unit
1156A For TRS-80 Exp. interface
purchased before 4/1/79
1156B For TRS-80 Exp. interface
purchased before 4/1/79
1156C Apple II C/I/195

1156D Exldy

The PIE 2.0

(Programma improved Editor)

An outstanding package with features of the
more expensive word Processing software,
including: Character/line insert and delete;
complete cursor mobility; string search forward
and backward; single; conditional, or global
search and replace; move and/or copy blocks of
text; page scrolling, tabs, margins, paragraphing,
etc.

The time to create, edit, and complete a one
page document can be decreased by as much as
60%, when comparing this system to an ordinary
typewriter, comes complete with program
diskette and detailed documentation in an
attractive simulated leather binder.

Cat NO. 2562 4 im95

Apple ll 32K + Disk (3.2), Integer 9 #9

120 DAY

QUALITY GUARANTEE

This guarantee Is your assurance of receiving the
highest quality products every time you order
from Hobbyworld. If you are not satisfied with
the quality of the Item you purchased, simply
return it to us. All returns must be accompanied
by a copy of the sales receipt, and a brief
explanation of the reason for return is
requested. Guarantee does not Include damage
to kits from poor assembly practices. Refunds or
replacements are at our option, software and
books will be replaced with another copy only.
Hobbyworld is not responsible for typographical
errors.

®

HOBBYWORLD

ELECTRONICS, INC.

Call Toll-Free: USA (800) 423-5387 in California: (800) 382-3651
Local & Outside USA: (213) 886-9200

Disk/Diskette Drive
Head Cleaning Kit

Diskette drive heads require periodic
maintenance to assure efficient and error-free
operation, unlike other peripheral devices, the
read/write heads on disk drives are extremely
difficult to clean without partially disassembling
the unit. But now, with Hobbyworld s disk drive
head cleaning kit, the user can clean these hard-
to-reach heads in just minutes! Available for both
5W and 8 ' drives, single and double sided.

Comes complete with two cleaning disks, 4 oz. of
CS-85 cleaning solution, and easy-pour dispenser.

Wt 12 oz.

Cat NO. 2499 8" Disk 99 W

cat NO. 2534 5 Vi” Diskette

FLYER, FEATURING...

Page after page of impressive state-of-the-art
products, included are computers, terminals,
disk-drives, printers and many more peripherals
that can add dimension to your personal
computing, we also stock computerized games
and toys, application boards, a large selection of
comprehensive software, electronics parts,
Integrated circuits, P.C. & soldering accessories
and much, much more

HOW TO ORDER

Minimum Order $15.00. Order by phone, mall, or
at our retail stores. Pay by check, Mastercharge,
visa or C.O.D. Please Include expiration date with
charge card orders. U.S. $$ only, include phone
number and magazine issue you are ordering
from. Add $1.25 for C.O.D. and shipping charges
from rates below.

Shipping Rates: U.S.A.

Ground: Add $2.25 for first 2 lbs. and 40c each
addt'l lb.

Air: Add $3.25 for first 2 lbs. and 70c each
addt'l lb.

Shipping Rates: Foreign
Ground: Add $3.00 first 2 lbs. and 60c each
addt'l lb.

Air: Add $11.25 for first 2 lbs. and $5.00 each
addt'l lb.

Prices valid through month of Issue.

Not responsible for typographical errors. Some
items subject to prior sale or quantity limits. 120
Day Guaranteed Satisfaction.

Exception: Partially assembled kits, abuse or
misuse.

19511 BUSINESS CTR. DR. DEPT K10 NORTHRIDCE, Cfl- 9132a

Power Supplies! Power Supplies! Power Supplies! SOLID STATE!! (5)

We got ’em! Take your pick . . .

These units are ideal for micro computers. They have been removed from equipment, checked out and
guaranteed.

1— 5 volts @ 8 amps + 12 volts @ 2 amps + 6 volts @ 75 MA. Power supply has a 3-wire line cord and fused. Dimensions:

IOV 2 ” x5Vi” x 4 'A”. Shipping weight: 16 lbs 37.50 ea. 2/70.00

2— Model 81 8, 5 volts at 1 5 amps + 12 volts at 4 amps-1 2 volts at 2 amps, (with line cord) 35.00 ea. 2/65.00

3— -l- 5 volts at 5 amps ± 12 volts at 500 ma. + 6 volts at 25 ms. (line cord included) 32.95 ea. 2/60.00

4— Elexon, multi output. Input: 120/240 AC, ±10%, 47-63 hz; output: 1) 12V, 1.5A, DC, OVP; 2) 12V,

1 .5A, D.C., OVP. New, in box with operating instructions 31 .50

5— Power Design, Model 1210, constant voltage, DC. P.S. input: 105-125 A.C., 55 to 440 hz. Output:

1-12 volts, 0-10 amps, DC. continuously adjustable output voltage and current limiting 139.00

COMPUTER GRADE CAPACITORS . . .

18.000 mfd 10 VDC
4,400 mfd 20 VDC

46.000 mfd 20 VDC
3.000 mfd 25 VDC

1.25

1.00

2.50

1.00

11.000 mfd 25 VDC

35.000 mfd 35 VDC

10.000 mfd 50 VDC

22.000 mfd 60 VDC

1.50

3.50

2.50
3.75

4.000 mfd 75 VDC

1.000 mfd 100 VDC
6,800 mfd 100 VDC
4,700 mfd 150 VDC

1.75
1.00
3.50

3.75

WIRE WRAP BOARDS

These boards are pre-wired and removed from equipment. Easy to un-
wrap for setting up your own board, contains mostly 14-pin 1C sockets
with individual pin connections. Each board has VCC and ground
planes.

Smaller board measures 6 V 2 ” x 6 ” and has 40 to 50 sockets.

Larger board measures 13 V 2 ” x6” and has 75 to 100 sockets.

Reduced prices

$7.50 ea. 2/$14.00
$12.50 ea. 2/$23.00

DIABLO System Disc Drive

SERIES 40, MODEL 43
100 tracks per inch, total capacity of 50 mega-
bits, w/Model 429 power supply, sector
counter, 24 sectors, 1 fixed disc, 1 removable
disc, average access time 38 ms, PPM: 2600,
dimensions: 10 5/16” high, fits in standard
rack, equipped with full extension slides, ex-
cellent used condition. Shipped freight col-
lect.

$2495

HEWLETT PACKARD model 200CD/rack
mounted AUDIO OSCILLATOR freq:5hz to
600khz output: 1 60mw $1 65.00

HEWLETT PACKARD model 400D
ANALOG VACUUM TUBE VOLTMETER
freq: lOhz to 4mhz voltmeter range: 1 mv to
300vac in 12 ranges $85.00

TRANSFORMERS

ISOLATION STEP-DOWN TYPE

Primary: 230/1 15V, 50/60
CPS, Secondary: 1 1 5 volts
output 250 VA.

$ 13.95

EACH

IMC MAGNETICS
SUPER BOXER FANS

Unused, Model WS2107FL
-310, 220/240 VAC, .3
amps, 50/60 hz, 41 1/16” x
4 11/16” x 1 1/2”

$ 8.95

Clock Crystal Oscillators— TTL, Vectron, type CO-
231T. Crystal freq. 4.9152 mhz. Input voltage 5 VDC
±. Output: Drives 10 TTL Loads Logic “0”: 0.4V
max., sink 16ma. Logic “1” 2.4V min source 2 ma.
(above 50 mhz drives 2 Schottky TTL loads). Tuning
adjust, with nominal range of ±30 ppm below 25
mhz and 15 ppm above 25 mhz. R.F.E. 1Va”x
1 V* ” x Va” $13.95

SG-132 SWEEP SIGNAL GENF^OR

FREQ: 15 TO 400 \ \

Output: AM & FM: CW * ,u at any fre-
quency. Crystal omhz or ± 10B. Fre-
quency acv i oscilloscope for observing

waveforms. $329

TRENDLINE PHONES

Manufactured by I.T.T.

These units have rotary dials. Colors are: white, black, red, and
green. They are packaged and have 6 -foot cord and installation
instructions. Used, but in good operating condition.

34.50 WALL TYPE

Minimum order $25.00. Items offered subject to prior sale. FOB, Brockton, Mass. Money order or check w/order. Shipments and
handling add 5%. Shipments by parcel post or UPS. No CODs. Mass, residents add 5% sales tax.

WALLEN

ELECTRONICS CO. INC. Tel: (617) 588-6440-6441
is 45 108 SAWTELL AVE, BROCKTON, MA. 02402

ELECTRONIC
COMPONENTS
TEST EQUIPMENT
CONNECTORS- WIRE

234 Microcomputing, October 1980

AIM 65

BY ROCKWELL INTERNATIONAL

AIM 65 is fully assembled, tested and warranted. With the
addition of a low cost, readily available power supply, it’s
ready to start working for you.

AIM 65 features on-board thermal printer and
alphanumeric display, and a terminal-style keyboard. It
has an addressing capability up to 65K bytes, and comes
with a user-dedicated IK or 4K RAM. Two installed 4K
ROMS hold a powerful Advanced Interface Monitor
program, and three spare sockets are included to expand
on-board ROM or PROM up to 20K bytes.

An Application Connector provides for attaching a TTY
and one or two audio cassette recorders, and gives exter-
nal access to the user-dedicated general purpose I/O lines.

Also included as standard are a comprehensive AIM 65
User’s Manual, a handy pocket reference card, an R6500
Hardware Manual, an R6500 Programming Manual and an
AIM 65 schematic.

AIM 65 is packaged on two compact modules. The
circuit module is 12 inches wide and 10 inches long, the
keyboard module is 12 inches wide and 4 inches long.

They are connected by a detachable cable.

THERMAL PRINTER

Most desired feature on low-cost microcomputer systems . . .

• Wide 20-column printout

• Versatile 5x7 dot matrix format

• Complete 64-character ASCII alphanumeric format

• Fast 120 lines per minute

• Quite thermal operation

• Proven reliability

FULL-SIZE ALPHANUMERIC KEYBOARD

Provides compatibility with system terminals . . .

• Standard 54 key, terminal-style layout

• 26 alphabetic characters

• 10 numeric characters

• 22 special characters

• 9 control functions

• 3 user-defined functions

TRUE ALPHANUMERIC DISPLAY

Provides legible and lengthy display . . .

• 20 characters wide

• 16-segment characters

• High contrast monolithic characters

• Complete 64-character ASCII alphanumeric format

RNB> ENTERPRIS

INCORPORATED

PROVEN R6500 MICROCOMPUTER SYSTEM DEVICES

Reliable, high performance NMOS technology . . .

• R6502 Central Processing Unit (CPU), operating at 1
MHz. Has 65K address capability, 13 addressing modes
and true index capability. Simple but powerful 56
instructions.

• Read/Write Memory, using R2114 Static RAM devices.
Available in IK byte and 4K byte versions.

• 8K Monitor Program Memory, using R2332 Static ROM
devices. Has sockets to accept additional 2332 ROM or
2532 PROM devices, to expand on-board Program
memory up to 20K bytes.

• R6532 RAM-Input/Output-Timer (RIOT) combination
device. Multipurpose circuit for AIM 65 Monitor functions.

• Two R6522 Versatile Interface Adapter (VIA) devices,
which support AIM 65 and user functions. Each VIA has
two parallel and one serial 8-bit, bidirectional I/O ports,
two 2-bit peripheral handshake control lines and two
fully-programmable 16-bit interval timer/event counters.

BUILT-IN EXPANSION CAPABILITY

• 44-Pin Application Connector for peripheral add-ons

• 44-Pin Expansion Connector has full system bus

• Both connectors are KIM-1 compatible

TTY AND AUDIO CASSETTE INTERFACES

Standard interface to low-cost peripherals . . .

• 20 ma. current loop TTY interface

• Interface for two audio cassette recorders

• Two audio cassette formats: ASCII KIM-1 compatible
and binary, blocked file assembler compatible

ROM RESIDENT ADVANCED INTERACTIVE MONITOR

Advanced features found only on larger systems . . .

• Monitor-generated prompts

• Single keystroke commands

• Address independent data entry

• Debug aids

• Error messages

• Option and user interface linkage

ADVANCED INTERACTIVE MONITOR COMMANDS

• Major Function Entry

• Instruction Entry and Disassembly

• Display/Alter Registers and Memory

• Manipulate Breakpoints

• Control Instruction/Trace

• Control Peripheral Devices

• Call User-Defined Functions

• Comprehensive Text Editor

LOW COST PLUG-IN ROM OPTIONS

• 4K Assembler— symbolic, two-pass , A 65.010 $ 79.00

• 8K BASIC Interpreter A65-o2o $ 99.00

POWER SUPPLY SPECIFICATIONS

• +5 VDC ± 5% regulated @ 2.0 amps (max)

• +24 VDC ± 15% unregulated @ 2.5 amps (peak)

0.5 amps average

PRICE: $389.00 (IK RAM) $439.00 (4K RAM)

Plus $4.00 UPS (shipped in U.S. must give street address),
$10 parcel post to APO’s, FPO’s, Alaska, Hawaii, Canada,
$25 air mail to all other countries
AIM 65 USER MANUAL $5.00 plus $1.50 shipping & handling.

We manufacture a complete line of high quality expansion
boards. Use reader service card to be added to our mailing
list, or U.S. residents send $1.00 (International send $3.00
U.S.) for airmail delivery of our complete catalog.

We’ve Expanded Again!

Note our new address.

EE S W Fairmount Avenue

✓"52

Phoenix AZ. 8501 7
(602)265-7564

IMew Releases for the TRS-80*

Mail/List from Galactic Software Ltd.

A Mailing List for the TRS-80 Model I or Model II

Instant Software always tries to provide you with the best
software on the market. Although the Mail/File mailing list
program is not published by us, it is so good that we want you
to try it.

We have two versions of this mailing list. Pkg. 5000RD is for
the Model I with the 5-inch disk drive and Pkg. 5001 RD is for
the Model II with the 8-inch disk drive. The programs are
essentially identical except for the storage media and their
respective capacities.

With the 5-inch drive, you can store up to 600 names per
disk without DOS, or 300 names per disk with DOS. With the
8-inch drive, you can store up to 2500 names per disk, with or
without DOS. (If your list is larger than the single disk max-
imum, it can be distributed over several disks.)

The program maintains separate alphabetical and ZIP code
files under constant sort. When you add a name to your list it
will be inserted into its correct position in the files. You will
never have to sort your list, it will always be ready to print
labels.

The program will record your data in nine fields: two for
NAME, and one each for ADDRESS, CITY, STATE, ZIP CODE,
PHONE NUMBER, PHONE EXTENSION, and a five character
CODE field. When you print labels, you have a choice of three
different label formats: a three line label, a four line label or a
user-defined label. In the three line and user-defined label for-
mats, you may include a message line on your label.

The best feature of this program is the sort process that
lets you determine which labels will be printed. You may
specify either alphabetical or ZIP code order for all or any part
of your list. For example, you can print labels for everyone on
your list whose name begins with the letter A, or for all of
those people who have the same ZIP code. You can even print
labels for only those people named Jones, who are living in a
given city or state. (Note: The Model II version can search for
both first and last names, e.g., John Jones.) Furthermore, you
can choose to print labels by using any single field (i.e.,
specific cities, states, phone numbers, etc.). You may assign
specific codes to any name in the CODE field. For example,
ACT could stand for active accounts, and IN ACT for inactive
accounts. If you wanted to send a letter to all of your inactive
accounts, you would specify the CODE INACT, and labels
would be printed only for your inactive accounts. When you
print labels, you may specify up to nine different CODES at
one time. If your data matches any one of the CODES, a label
will be printed.

Files created with the Model I version of this program can
be transferred to the Model II version, when you upgrade your
hardware.

Package 5000RD requires the following minimum system:

1. A TRS-80 Model I Level II with 16K RAM.

2. An Expansion Interface with 16K RAM (or more).

3. One (or more) mini-disk drives.

4. A compatible printer (80 or 132 columns).

5. TRSDOS version 2.3.

Order No. 5000RD (Model I version) $99.00

Package 5001 RD requires the following minimum system:

1. A TRS-80 Model II with 64K of RAM.

2. Additional Expansion Unit drives (optional).

3. Model II TRSDOS version 1.2.

4. A compatible printer (80 or 132 column).

Order No. 5001 RD (Model II version) $199.00.

*A trademark of Tandy Corporation

Basic Math Program from EMSI

Although we do not publish this package, it is so out-
standing that we would be remiss if we didn’t offer it to you,
our customers. The Basic Math Program is a comprehensive
math teaching package divided into six sections. It is, also,
the best educational software that we have seen for teaching
arithmetic skills. The package was designed and created by a
certified math teacher with 15 years of programming ex-
perience.

The first three programs in the package comprise: Whole
Number Arithmetic by Teaching Objective. This set includes
lessons in Addition, Subtraction and Multiplication. (Whole
Number Division by Teaching Objective will be available
soon.) The fourth program is Fractions and Mixed Number
Arithmetic. Logic and Deductive Reasoning is the fifth pro-
gram in the set. The Metric-English Conversion program
rounds out the series.

You, the teacher, can choose a variety of options from the
MENU, so as to custom-tailor both practice and test sessions.
The program options include: Number of problems/session,
Level of problem difficulty, Number of seconds per problem,
Type of assistance to be offered (digit by digit or retry), Type
of reward, as well as options specific to the Addition and the
Subtraction sections.

This package includes an excellent, 60 page Teacher’s
Manual that explains how to use all program features -
even for those people who have no prior experience with a
computer system. The manual introduces and explains all of
the teaching objectives in terms of the specific skills to be
mastered. It contains detailed instructions on how to use the
computer. (It even explains the proper cassette loading pro-
cedure in easily understood terms.) The manual goes on to
show you exactly what material will appear on the computer
screen, and how to select the program options. It explains
how to use the Analysis of Session Results feature, which
shows not only the number of problems/number correct, but
displays the actual problems given, notes if an incorrect digit
was entered, whether it was corrected during the session and
whether the student used the HELP feature.

The Fractions and Mixed Number Arithmetic program
shows the student every step of how to solve these problems.
It waits for the student to enter each answer and — if he/she
has made an error — provides a review of the process, so that
the error can be found. It can also be run as a “fraction/mixed
number calculator”.

The Deductive Reasoning program is a modified and much
improved Mastermind-type exercise. It may be played as a
game, or used to exemplify the rigorous nature of valid in-
ference.

The Metric/English Conversion program will convert quan-
tities (length, area, volume and weight) from Metric to English,
or English to Metric. It includes all of the most commonly
used units of measure.

First there was the revolution of Computer Assisted In-
struction. Now, there’s the evolution of this extraordinary
“teacher’s aide”.

Order No. 5002R $80.00

TO ORDER: Look for these programs at the dealer nearest
you (see list of dealers on page 205). If your store doesn’t
stock Instant Software send your order with payment to:
Instant Software, Order Dept., Peterborough, N.H. 03458
(Add $1.00 for handling) or call toll-free 1-800-258-5473
(VISA, MC and AE accepted).

Instant Software

M

PETERBOROUGH, N.H. 03458
603-924-7296

236 Microcomputing, October 1980

New Releases for the TRS-80'

Utilities

We’re proud to present three disassemblers for the TRS-80. For
speed and simplicity, we recommend The Disassembler. For
complex disassemblies, especially if you wish to make altera-
tions, you may prefer one of our Labeling Disassemblers, either
TLDIS or DLDIS.

TLDIS & DLDIS

You’ve bought a super machine-code
program, but now wonder how it works.

Maybe you even used a quick PEEK
routine to glance through it when it was
in memory. If so, you definitely noticed
the complete lack of comments in the
code, making it almost impossible for
you to decipher and understand it.

Well, Instant Software’s Labeling
Disassemblers are the answer to your
problem.

TLDIS (Tape-based Labeling Disas-
sembler) and DLDIS (Disk-based Label-
ing Disassembler) are three-pass, label-
assigning disassemblers which assign
labels (where appropriate) to the
routines in a machine-language pro-
gram. Their output is almost identical to
that of a hand-assembled source code.

You can send the disassembly to a
lineprinter (Radio Shack parallel port) for
either TLDIS or DLDIS. (The difference
between these utilities is the storage
mode of the disassembly.)

TLDIS can send the disassembly to
cassette tape, DLDIS can send it to disk;
both send it to the video monitor. The
stored disassembly from TLDIS may be
reassembled with Radio Shack’s
EDTASM(™) — the disassembly from
DLDIS, with Apparat’s extension of ED-

TASM(TM).

Because of the use of labels, it is a
simple matter to change any object code
program by disassembling it and then

The Disassembler

This is a single-pass, hex-notation
disassembler that will send its output
either to tape or to a lineprinter (Radio
Shack parallel port). The tape output is
directly compatible with Tandy’s ED-
TASMCTM) Thus, you can take an object
code tape, disassemble and output it to
tape, then use EDTASM(™) to add,
delete, change and even re-assemble
your new version.

In addition, it displays the displace-
ment and absolute address of any
relative jumps made by the disassem-
bled program. It also displays any ASCII
characters used in a LD or CP opcode.

Sample output from the Disassembler

making changes to the resultant source
code, without losing track of jump/load
addresses. Labels start with “AAOO” and
increment up, in even numbered steps
(AA02, AA04, etc.). The odd numbers
(AA01, AA03, etc.) are left for you to use
for the source code during reassembly.

The printing of the disassembly may
be temporarily halted by using [SHIFT]
@ Gust as in BASIC) or it may be ended
by pressing the [BREAK] key. It also has
a comments column to display ASCII
charachters used in a LD or CP opcode.

Because TLDIS and DLDIS work only
on in-memory programs, they may be
relocated in memory to avoid conflict
with the program you disassemble.

The next time you need to “climb in-
side” a machine-code program, take
DLDIS or TLDIS with you. We promise
that it will be an easier journey.

Order No. 0230R (TLDIS) $14.95
Order No. 0231 RD (DLDIS) $1 9.95

BYTE

MACHINE

LINE

MNEMONIC

COMMENTS

NUM.

CODE

NUM.

COLUMN

706E

22057 B

00053

LD

(7B05H),HL

7071

183B

00054

JR

$ + 3DH

70AEH

7073

FE52

00055

CP

52H

= “R”

7075

2007

00056

JR

NZ,$ + 09H

707EH

7077

CD8F70

00057

CALL

708FH

H means the number is HEX
$ means current location counter.

Since the Disassembler works only on
in-memory programs, it has been made
relocatable so that you may move it
around in memory to avoid conflict with
the program you wish to disassemble.
As an added option, you may also jump
to memory locations and transfer con-
trol between Disassembler and other
utility programs in your computer.

The Disassembler, use it to examine
and analyze any machine-code pro-
gram!

Order No. 0232R $9.95

Terminal-80

The Terminal-80 package lets your
TRS-80 communicate with the rest of the
world. These programs give you control
of the RS-232 port of your Expansion In-
terface.

You can connect one or more serial
terminals to your TRS-80. Your computer
will accept input from the RS-232 port
just as if it were entered from the
keyboard. Thus, you can use your com-
puter from a remote terminal without
having to move your equipment.

The TRS-80 can also be transformed
into a “dumb” terminal. You can use it in
a time-sharing situation to talk to “big”
computers via a modem. All data that
you type in will go out through the
RS-232 port and all incoming data will be

displayed on the screen.

You can transfer programs over the
phone lines. Just load a program into the
TRS-80. The LPRINT/LLIST command
will transfer the program to a receiving
computer via the RS-232 port.

Using the upper/lowercase modifica-
tion of the TRS-80 is simplified. (You
must have the modification kit installed
first or follow the detailed instructions
included in this package.) Control
characters in Level II and Disk BASIC
will be properly displayed and all func-
tions such as CHR$ will work correctly.

This package even includes a BASIC
program to set the baud rate. You won’t
have to tear apart your Expansion Inter-
face if you use more than one configura-
tion.

There are thousands of TRS-80 com-
puters in the world. Let’s get together
and talk to each other— with the Termi-
nal-80 from Instant Software.

This package requires the following
minimum system:

1. A TRS-80 with 16K of memory.

2. An Expansion Interface.

3. An RS-232 Serial Interface (e.g.,
Radio Shack’s No. 26-1145 or the
equivalent).

4. An optional upper/lowercase
modification kit.

Order No.01 30R (cassette-based) $24.95.

WRITE FOR OUR NEW CATALOG!

Instant Software

" 40 *A trademark of Tandy Corporation

PETERBOROUGH, N.H. 03458
603-924-7296

i/ 0 Reader Service index— page 241

Microcomputing, October 1980 237

WAMECO

THE COMPLETE PC BOARD HOUSE
EVERYTHING FOR THE S-IOO BUSS

* FPB-1 FRONT PANEL BOARD FOR 8080A AND Z80
SYSTEMS IMSAI COMPATIBLE.

PCBD $56.95 KIT $1 75.00

* MEM-2 16K RAM 2114’s. ADDRESSABLE IN 4K
BOUNDARIES.

PCBD .... $33.95 KIT (LESS RAMS) .... $80.95

* EPM-2 16/32K ROM USES 2716 OR 2708. ADDRESS-
ABLE IN 4K BOUNDARIES.

PCBD .... $33.95 KIT (LESS ROMS) .... $74.95

* CPU-1 8080A PROCESSOR BOARD WITH VECTOR
INTERRUPT.

PCBD $33.95 KIT $124.95

* IOB-1 I/O BOARD. ONE SERIAL, TWO PARALLEL

WITH CASSETTE. PCBD $33.95

* FDC-1 FLOPPY DISC CONTROLLER BOARD USES

1771. PCBD $45.95

* QMB-12 13 SLOT MOTHER BOARD.

PCBD $42.95 KIT $125.95

* QMB-9 9 SLOT MOTHER BOARD.

PCBD $35.95 KIT $109.95

* PTB-1 POWER SUPPLY AND TERMINATOR BOARD.

PCBD $29.95 KIT $49.95

* RTC-1 REAL TIME CLOCK BOARD WITH TWO
INTERRUPTS.

PCBD $29.95 KIT $79.95

* MEM-1 8K RAM, USES 2102’s.

PCBD $33.95 KIT (LESS RAM) $71.95

* EPM-1 4K 170Z BOARD.

PCBD .... $29.95 KIT (LESS ROM) $59.95

FUTURE PRODUCTS: 80 CHARACTER VIDEO BOARD.

Z-80 CPU BOARD WITH ROM, 8 PARALLEL PORT I/O BOARD

DEALER INQUIRIES INVITED, UNIVERSITY DISCOUNTS AVAILABLE

AT YOUR LOCAL DEALER

MOST PRODUCTS FOR IMMEDIATE SHIPMENT. NO 4-8 WEEK DELAYS REQUIRED FOR OTHERS.

W7TJC

/nc.

WAMECO, INC., P. O. BOX 877 • 455 PLAZA ALHAMBRA • EL GRANADA, CA 94018 • (415) 726-6378

CALIFORNIA COMPUTER SYSTEMS

16K RAM BOARD. Fully buffered addressable in 4K
blocks. IEEE standard for bank addressing 2114’s.

PCBD $28.95 Kit 450 NSEC ..$249.95

PT-1 PROTO BOARD. Over 2,600 holes 4" regula-
tors. All S-100 buss functions labeled, gold fingers.
PCBD $28.95

PT-2 PROTO BOARD. Similar to PT-1 except set-
up to handle solder tail sockets. PCBD ..$28.95

CCS MAIN FRAME. Kit (S-100) $339.95

APPLE EXTENDER. Kit $22.95

APPLE IEEE INSTRUMENTATION INTERFACE
KIT 7490. Kit $275.00

ARITHMETIC PROCESSOR FOR APPLE 7811A.
Kit $350.00

APPLE ASYNCHRONOUS SERIAL INTERFACE
7710A. Kit $89.95

APPLE SYNCHRONOUS SERIAL INTERFACE

771 2A. Kit $89.95

ALL OTHER CCS PRODUCTS AVAILABLE

PB-1 2708 & 2716 Programming Board with pro-
visions for 4K or 8K EPROM. No external supplies
required. Textool sockets. Kit $143.00

CB-1 A 8080 Processor Board. 2K of PROM 256
BYTE RAM power on/rest Vector Jump Parallel
port with status. Kit .. $146.00 PCBD $31.95

VB-3 80x24 VIDEO BOARD. Graphics included.
4MHZ $379.95

IO-4 Two serial I/O ports with full handshaking
20/60 ma current loop: Two parallel I/O ports.
Kit $168.00 PCBD $31.95

VB-IC 64 x 16 video board, upper lower case Greek
composite and parallel video with software, S-100.

Kit $143.00

CB-2 Z80 CPU BOARD. Kit $199.95

AIO APPLE SERIAL/PARALLEL $144.95

ALL OTHER SSM PRODUCTS AVAILABLE

[WfnCjjnC' WAMECO INC.

FDC-1 FLOPPY CONTROLLER BOARD will drive
shugart, pertek, remic 5" & 8” drives up to 8 drives,
on board PROM with power boot up, will operate

with CPM™ (not included). PCBD $43.95

FPB-1 Front Panel. IMSAI size, hex displays. Byte,

or instruction single step. PCBD $48.50

MEM-1A 8K x 8 fully buffered, S-100, uses 2102

type rams. PCBD $28.95

QM-12 MOTHER BOARD, 13 slot, terminated, S-100

board only $39.95

CPU-1 8080A Processor board S-100 with 8 level

vector interrupt. PCBD $28.95

RTC-1 Realtime clock board. Two independent in-
terrupts. Software programmable. PCBD $25.95

EPM-1 1702A 4K Eprom card. PCBD $25.95

EPM-2 2708/2716 16K/32K EPROM CARD.

PCBD $28.95

QM-9 MOTHER BOARD. Short Version of QM-12.

9 Slots. PCBD $33.95

MEM-2 16K x 8 Fully Buffered 2114 Board.

PCBD $28.95

PTB-1 POWER SUPPLY AND TERMINATOR BOARD.

PCBD $28.95

IOB-1 SERIAL AND PARALLEL INTERFACE.

2 parallel, one serial and cassette.

PCBD $28.95

2708 $ 9.49 2114L 450 NSEC $5.99

2716 $35.95 2114L 200 NSEC $6.99

(415) 726-7593

P. O. Box 955 • El Granada, CA 94018

Please send for 1C, Xistor and Computer parts list

OCT. SPECIAL SALE
ON PREPAID ORDERS

(Charge cards not included on this offer)

RAM SALE

MEM-2, PCBD $25.95

MEM-2 -I- PARTS LESS RAM $49.95

MEM-2 MIKOS #7 450 NSEC $199.95

MIKOS PARTS ASSORTMENT
WITH WAMECO AND CYBERCOM PCBDS
MEM-2 with MIKOS #7 16K ram

with L2114 450 NSEC $229.95

MEM-2 with MIKOS -13 16K ram

with L2114 200 NSEC $249.95

CPU-1 with MIKOS *2 8080A CPU $99.95

QM-12 with MIKOS *4 13 slot mother

board $110.95

RTC-1 with MIKOS -5 real time clock $65.95

EMP-1 with MIKOS *10 4K 1702 less

EPROMS $ 49.95

EPM-2 with MIKOS *11 16-32K EPROMS

less EPROMS $65.95

QM-9 with MIKOS *12 9 slot mother

board $99.95

FPB-1 with MIKOS *14 all parts

for front panel $144.95

MIKOS PARTS ASSORTMENTS ARE ALL FACTORY MARKED
FARTS. KITS INCLUDE ALL PARTS LISTED AS REQUIRED
FOR THE COMPLETE KIT LESS PARTS LISTED. ALL SOCK-
ETS INCLUDED.

LARGE SELECTION OF LS TTL AVAILABLE

PURCHASE $50.00 WORTH OF LS TTL AND GET
10% CREDIT TOWARD ADDITIONAL PURCHASES.
PREPAID ORDERS ONLY.

VISA or MASTERCHARGE. Send account number, interbank num-
ber, expiration date and sign your order. Approx, postage will
be added. Check or money order will be sent post paid in U.S.
If you are not a regular customer, please use charge, cashier's
check or postal money order. Otherwise there will bo a two-
week delay for checks to clear. Calif, residents add 6% tax.
Money back 30-day guarantee. We cannot accept returned IC’s
that have been soldered to. Prices subject to change without
notice. $10 minimum order. $1.50 service charge on orders
less than $10.00.

238 Microcomputing, October 1980

Computers, Disk Systems

SUPERBRAIN

By INTERTEC

32K or 64K (Double or Quad Density units
available). Uses two Z-80 CPU's. Commercial-
type terminal with 12" monitor. Dual double
density minifloppies. Over 350 kilobytes of
storage (twice that with quad density drives).
Two serial RS232 ports, I/O ports standard.
Expandable with optional S-100 S-100 inter-
face. Comes with CP/M™ 2.2 operating sys-
tem. MiniMicroMart includes BASIC inter-
preter and can supply a wide range of CP/M
Development and Application software.

w/32K Double Density, List $2995 . $2685

w/64K Double Density, List $3345 $2883

w/64K Quad Density, List $3995 $3595

W/64K Quad — MiniMicroMart

Upgrade Special $3395

MICROMATION

computer with dual density
8" floppies (1 megabyte). Rack or vertical
mounting. Systems with double-sided drives,
hard disks, and multi-user (MP/M).

Z+ 100 64K RAM, Computer, $2495. . $2099

Z + 120 Includes two 8" disks, $4995 . . . $4199

"Z" system features new distributed processing
multi-user concept with one Z-80 per user, with
Z-80 for MP/M (Master Satellite concept).

AS LOW AS $11,899!

SD SYSTEMS

SDS-100, w/32K RAM, $6995 . . $5945

SDS-200, List $8995 $7645

RADIO

SHACK

TRS-80™

10% OFF!

INTERSYSTEMS

formerly ITHACA AUDIO

DPS-1, List $1795

LIMITED TIME $1

The new Series II CPU Board features a 4 MHz
Z-80A CPU and a full-feature front panel. 20-
slot actively terminated motherboard, with 25
amp power supply (50/60 Hz operation, incl.
68 cfm fan).

COMPLETE SYSTEM with InterSystem 64K
RAM, I/O Board w/priority interrupt and
double density disk controller board. Full 1-year
warranty. List $3595

LIMITED TIME $2895*

Above without disk controller,

List $3195 LIMITED TIME $2539*

* Prices good until September 15, 1980.

HEWLETT-PACKARD

HP-85 A

Desk-top computer — Call for Price!

MORROW

THINKER TOYS®
DISCUS M26™

THINKER TOYS®
DISK SYSTEMS

Now includes CP/M® 2.2

Discus 2D, List $1199. . ...$1019

Discus 2D, dual-drive. List $1994 $1694

Discus 2 + 2, Assem., List $1549 $1319

Dual Discus 2 + 2, Assem., $2748 $2335

All Morrow systems now include CP/M® 2. 2

✓*226

NORTH STAR
DOUBLE DENSITY
CONTROLLER BOARDS

Kit, List $399

OUR PRICE

Assembled and Tested, List $499 $399

In Stock — First Time in 2 Years!

FANTASTIC SAVINGS
on a "QUAD" DENSITY
HORIZON UPGRADE

North Star Double Density Controller Board
(see above) and a quad density MPI-52 (fea-
tures superior disk handling and door mechan-
ism.

MDS-H-MQ/K Kit form .

List $999 OUR PRICE $699

MDS-H-MQ/A Assembled form, List $1099

$759

Shipping and insurance: Add $6.

NORTH STAR MDS-A
Double Density Mini
Floppy Disk System

Double Density, Kit

List $799 OUR PRICE $669

Assembled and Tested $719

Quad Version, Kit, List $836

Assembled, List $1099 $896

Above MDS-A units do not include cabinet or
power supply.

Shipping and Insurance: Add $7.50.

Super Special!

North Star
Controller Board,

Drive, Cabinet, A^AQ
and Power Supply Y # ww

Complete system similar to above but also
includes a cabinet and an assembled /tested
power supply for the drive (silver finish). Your
choice of Shugart SA-400 or MPI-51 Double
Density Drive or MPI-52 quad density drive
(MPI drives feature improved door and disk
handling mechanism).

w/Controller Bd. kit, SA-400 $709

w/Controller Bd. kit, MPI-51 $709

w/Controller Bd. kit, MPI-52 $809

w/Assembled Bd. and SA-400 $769

w/Assembled Bd. and MPI-51 $769

w/ Assembled Bd. and MPI-52 $869

Shipping and Insurance: Add $6.

For converting existing Horizon 2 to quad,

order additional MPI-52

MPI-52 Quad Density Drive $379

Turn Page

Terminals and Printers!

TELEVIDEO TVI-912C

SOROC

TI-810

Upper and lower case, 15 baud rates: 75 to
19,000 baud, dual intensity, 24 x 80 character
display, 12 x 10 resolution. Numeric pad. Pro-
grammable reversfole video, auxiliary port,
self-test mode, protect mode, block mode,
tabbing, addressable cursor. Microprocessor
controlled, programmable underline, line and
character insert /delete. "C" version features
typewriter-style keyboard. List $950

OUR PRICE $789

920C (with 1 1 function keys, 6 edit keys and
2 transmission mode keys, List $1030

ONLY $849

Intertec

EMULATOR

Software compatible with a Soroc IQ-120,
Hazeltine 1500, ADM-3A or DEC VT-52. Fea-
tures block mode transmission and printer port;
12" anti-glare screen; 18-key numeric keypad;
full cursor control. List $895 ,

OUR PRICE $729

Intertec INTERTUBE II

List $995 ONLY $799

12" display, 24 x 80 format, 18-key numeric
keypad, 128 upper/lower case ASCII charac-
ters. Reverse video, blinking, complete cursor
addressing and control. Special user-defined
control function keys, protected and unpro-
tected fields. Line insert/delete and character
insert/delete editing, eleven special line draw-
ing symbols.

IQ-120

List $995

SPECIAL

IQ-140 List $1495

SPECIAL $1149

TI-810 Basic Unit, $1895 . ONLY $1695
TI-810 w/full ASCII (Lowercase), vertical
forms control, and compressed print . $1895
TI-745 Complete printing terminal
with acoustic coupler. List $1695 .... $1399

HAZELTINE

1500

ONLY

$879

1410 w/numeric keypad. List $900 $749

1420 w/lower case and numeric pad 849

1510, List $1395 1089

1520, List $1650 1389

PAPER TIGER"

a i

IDS-440 Paper Tiger, List $995 . $895

w/graphics option, incl. buffer, $1194 . . $989
TRS-80 cable 45

BANTAM 550

From Perkin-Elmer

ONLY

$799

with

anti-glare

CRT

ONLY $829

CENTRONICS

PRINTERS

NEW 730, parallel, friction, tractor . . . $679

NEW 737 parallel, friction, tractor $849

779-2 w/tractor (same as TRS-80 Line
Printer I), List $1350 1049

702 120 cps, bi-direct., tractor, VFU 1995

703 185 cps, bi-direct., tractor, VFU .... 2395

704 RS232 serial version of 703, $2350 . . $1995

Terminal/Keyboard as well as
RO Printer Only models available.

CALL FOR PRICES!

OKIDATA

Microline 80 only $649

Tractor Feed Option $99

Serial interface $89

AXIOM IMP I $699

COMPRINT 912 w/parallel interf. $559
912 w/serial interface. List $699 $589

MICROTEK, List $750 $675

ANADEX 80-Col. Dot Matrix. . , ... $849

Above prices reflect a 2% cash discount (order prepaid prior to shipment). Add 2% to prices for credit
card orders, C.O.D.'s, etc. Prices are f.o.b. shipping point. Prices are subject to change and offers
subject to withdrawal without notice. WRITE FOR FREE CATALOG.

MiniMicroMart, Inc;

1618 James Street, Syracuse NY 13203 (315) 422-4467 TWX 710-541 0431

kilobaud

Peterborough NH 03458

MICROCOMPUTING™ L

1ST OF ADVERTISERS

Reader Service Number

Page

Reader Service Number

Page

Reader Service Number

Page

91

119

33

200

303

Personal Computer Systems

138

109

79

209

130

112

Personal Micro Computers, Inc

187

96

AEI

206

264

83

11

Programma International

139

497

24

128

Innovative Technolonv

184

202

Progressive Computing

130

249

94

40

Instant Software 15. 21. 166. 167. 236. 237

245

Purser Magazine

48

56

71

77

Integrand Research Corp

198

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Quant Systems

156

476

Anadex, Inc

23

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Integrated Service Systems, Inc

108

295

Quasar Data Products

65

319

155

475

22

44

Quest Electronics

225

495

APF Electronics, Inc

24

235

43

46

R&R Marketing

190

349

Apparat, Inc

123

225

Intertec Data Systems

3

485

Racet Computes

26

314

Apple-jack

201

279

Island Cybernetics

190

101

Racet Computes

207

Archabold Electronics

205

92

J.P.C. Products

39

482

Radio Shack

22

220

Aristo/Polks

146

41

Jameco Electronics

.228, 229

Radio Shack

105

237

Atec Systems

48

180

J.E.S. Graphics

146

•

Rainbow

189

192

. .184

164

Jini Microsystems

206

496

Rainbow Computing, Inc

26

193

Aurora Software

150

247

Joe Computer

179

491

Rainbow Computing, Inc

24

96

205

99

John Bell Engineering

181

142

Random Access, Inc

191

55

25

222

Kalglo Electronics

71

117

Realty Software Company

58

159

Beta Computer Devices

58

Kilobaud Microcomputing

52

RNB Enterprises

235

110

CFR Assoc

201

71, 99, 109, 201, 210, 215, 216-219

20

Robb Report

74

5

CMS Software Systems

81

124

Krell Software

140

102

Robertson Electronics

58

256

CPU Shop '

69

198

LNW Research

189

74

Rondure Company

91

79

C & S Electronics Mart, Ltd

173

312

Lake City Technical Products

156

321

SS-50 Computing.

83

148

California Computer Systems

28, 29

59

Leedex

149

281

Scelbi Publications

116

259

Edward Carlson

.80

Lifeboat Associates

10, 11

213

Scitek

130

58

Checks to go

48

219

MTI

146

208

Service Technologies Inc

80

28

Cleveland Consumer Computers

54, 55

207

Macrotronics

130

67

Sirius Systems

135

94

Compleat Systems

198

499

Manhattan Software, Inc

26

132

68 Micro Journal

150

90

CompuCover

118

479

Matchless Systems

23

66

Skyles Flectric Work*?

206

43

Compumart

222, 223

Mediamix

71

205

Slectronics

191

147

127'

129

Med Systems

47

231

Small Systems Software

95

32

97

492

Mendocino Software

24

146

Software Central

156

97

Computer Corner of NJ

213

108

Micro Architect

48

302

Software Dev. & Training Inc

94

18

Computer Design Labs

153

488

Micro Architect

322

Software Mart..

100 101

152

141

248

Micro Business World

211

294

Software Review

80

133

Computer Information Exchange, Inc....

189

216

The Micro Clinic

130

229

The Software Trader

184

115

Computer Instant Ads, Assoc

206

167

Micro Computer Industries

201

306

Spectrum Software

7Q

80

Computer Services

86

126

Micro Discount Service

35, 70

288

The Stocking Source

30

36

Computer Shopper

195

100

Micro Management Systems

171

162

Structured Program Designers

207

105

The Computer Stop

38

176

Micro Product Unlimited

70

179

Studio Magnetics Qo Inc

94

283

The Computer Stop

39

280

Micro Technical Products

115

152

Sun Technology

88

119

Computer Textile

200

344

Microcomputer Services Corp

215

25

Tab Books

77

26

Computers Unlimited

48

30

Microcomputer Technology Inc

123

189

Tab Sales Company

141

227

Computers Wholesale

188

260

The Microcomputer Warehouse

70

139

Tecmar, Inc

173

6

Computronics

161

487

MicroDaSys

24

118

Telecompute Integrated Systems

58

297

Concord Computer Components

230

68

Micromail

177, 179

328

Texas Computer Systems

215

494

Condor Computer Corporation

23

277

Micromint, Inc

49

65

Tora Systems 1 imited

200

271

Coosol Inc

172

253

Micron, Inc

186

313

Total Information Services

134

292

Coosol, Inc

38

123

Microsette Co

58

95

Total Information Services

134

141

Custom Electronics, Inc

70

86

Mid East Micro

155

171

MaxUleAdv &Mkt

152

Cybernetics, Inc

191

Midwest Scientific Instruments

cm

325

Urban Aggregates Inc

58

136

DAR Sales

150

*

Mikos

238

64

VR Data Corp

131

*

Data Analysis Systems

80

255

Miller Microcomputer Services

46

158

Vandata

78

*

Delta Systems

85

304

Mini Micro Mart

147

45

Wallen Electronics

234

73

Digital Graphic Systems

160

226

Mini Micro Mart

239

Wameco Inc

238

61

Digital Marketing

44

50

Mini Micro Mart

240

163

Wintek Corp

80

38

Digital Marketing

163

238

Mini Micro Mart

49

122

World Wide Flectronics

70

Digital Research Computers

226, 227

24

Money Disk

190

284

Word Wizards

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Digital Research Parts

164

477

Mountain Computer, Inc

23

337

X & Y Enterprises

108

199

Discount Computer Products..

130 133

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Mullen Computer Products

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Xymec

199

34

Dr. Daley

.’...87

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Multi Business Computer Systems

134

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Zapata Microsystems

24

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Duxbury Systems

23

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Mumford Micro Systems

140

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Dwo Quong Fok Lok Sow

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Myron Coy

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Ecosoft

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National Computer Shows

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Ecosoft

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Netronics R & D Ltd 70, 80, 125, 151, 231

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Educational Software Professionals

2m

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New England Business Service Inc

213

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Eighty Microcomputing

213

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New Technologies Co

80

Electravalue Industrial

133

NRI Schools

165

345

Electrolabs ... .

156

103

OEM Systems & Components

157

*This advertiser nrefers to be contacted directlv

93

Electronic Specialists

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Olensky Bros. Inc

62

47

Electronic Systems

220, 221

498

OK Machine & Tool Corp

20

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Emtrol Systems, Inc

20

54

OK Machine & Tool Corp

4

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Erickson Communications

183

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OK Machine & Tool Corp

121

57

Exatron

83

89

Omega Sales Co

141

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Exatron

110, 111

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Omnitek Systems

71

70

FMG Corp

63

29

Optimal Technology, Inc

134

169

Fair Radio Sales

152

310

Orange Micro

129

75

G W Computers Ltd

68

329

Orion Software

35

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Galactic Software Ltd

207

106

PAIA

155

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Gimix Inc

190 242

240

PCD Systems

98

481

Gimix, Inc

22

19

Paccom

155

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God bout

224

246

Pacific Exchanges

70

84

Mark Gordon Computers

126

274

Pacific Exchanges

86

239

Mark Gordon Computers

124

71

Pan American Electronics, A Radio Shack

236

Heath Co

CIV

Authorized Sales Center

198

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Heath Co

115

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Panasonic Comnanv

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13-16 Pprrnm Data

mi

For further information from our advertisers, please use the Reader Service card located on the last page.

Microcomputing, October 1980 241

lQQK

WHAT’S COOKING

on the FIFTY BUS

32K STATIC RAM BOARDS

Designed for use with:

★ Existing SS50 Systems ★ SS50C Extended Address Systems

• Assembled

• Burned In

• Tested

16K... $328.12
24K. . .$438.14
32K... $548.15

16K and 24K Versions are
socketed for 32K and require
only additional 2114’s for
expansion.

THE CLASSY CHASSIS

• 25 amp (5V) ferro- resonant constant voltage
power supply,

1 Heavy weight aluminum cabinet with 3 position
key switch, fan, and provisions for two 5” disk
drives;

6800/6809 Mother Board, fifteen 50 pin and
eight DIP-switch addressable 30 pin slots (gold
plated pins), fully decoded;

Baud rate generator on I/O section of
Mother Board.

I/O BOARDS

FEATURES:

for the 30 PIN BUS:

• Decoding for 4 Extended Address Lines (allows
memory decoding up to 1 megabyte)

• DIP-switch to set extended addressing or disable it

• 4 separate 8K blocks, addressable to any 8K
boundary by DIP-switch

• Each 8K block may be individually disabled

• Write protect either of two 16K sections

• Low power consumption — uses 2114L low
power RAMS

• Fully Socketed

• Gold Bus Connectors

• Guaranteed 2MHz operation

1 Port Serial $ 88.41

(RS 232 or 20MA, current loop)

2 Port RS 232 Serial 128.43

2 Port Parallel 88.42

lor the 50 PIN BUS:

AND N0W...GIMIX OFFERS YOU A
Choice of 6800 or 6809 CPU CARDS

You can order your system to fit your needs or select one of the below featured systems.
Please contact the factory for further information and availability.

Add as much memory as you need using GIMIX Static RAM Cards for the utmost in reliability.

32K 6800 SYSTEM $1,694.59

Includes: Chassis, 6800 CPU, 32K RAM BOARD, I/O card

32K 6809 SYSTEM $1,844.69

Includes: Chassis, 6809 CPU, 32K RAM BOARD, I/O card

32K 6809 PLUS SYSTEM $1 ,994.79

Includes: Chassis, 32K RAM BOARD, I/O Card, and features our 6809 PLUS CPU Card with the Time of Day
Clock option with battery back-up installed, as well as the 6840 Timer Package that provides 3 independent
16 bit counters.

8 Port RS 232 Serial 288.40

8 Port RS 232 Serial 318.46

with on board Baud Rate generator.

8 Port Parallel 198.45

BOTH 6809 SYSTEMS
FEATURE OUR
NEW TERMINAL BASED
GMXBUG 09 SYSTEM MONITOR

GMXBUG 09 includes advanced debugging
tools, utility, and memory manipulation
routines.

Both 6809 Systems:

★ Can be reconfigured to allow use of other
system monitors (OS-9 and SBUG-E)

★ Include IK of Scratchpad RAM on the CPU

This system also allows the following options to be added at additional cost:

• Battery back-up of the IK RAM by substituting CMOS parts.

• A 9511 or 9512 Arithmetic Processor.

• GIMIX or SWTP Dynamic Address Translators.

★ Allow optional software switching of system
monitors.

2MHz 6809’s at slight additional cost when they
become available.

EXPORT NOTES:

For 50Hz 230V C.V. POWER SUPPLY Add $30.00

80 x 24 VIDEO BOARDS — Specify Format (No Added Charge)

On Orders under $250.00 for a Single Board, or Chips, please Add $30.00 Handling and we will ship Air Mail Prepaid.
On all other orders we will ship via Emery Air Freight Collect, and we will charge no handling. All orders must be
prepaid in U.S. Funds. Please note that foreign checks have been taking about eight weeks for collection, so we
would advise wiring money or checks drawn on a bank account in the U.S. Our bank is the Continental Illinois
National Bank of Chicago, Account #73-32033. Visa or Master Charge also accepted.

FACTORY PRIME STATIC RAMS
2114L 450 ns . . $5.90 300 ns.. $6.40 200 ns. $6.90
4044 450 ns . . $5.90 250 ns . . $6.90

ADD $5.00 HANDLING ON ORDERS UNDER $200.00
GIMIX® and GHOST® are Registered Trademarks of GIMIX INC.

Phone, write, or see your dealer for details and
prices on our broad range of Boards and
Systems for the SS50/SS50C bus and our AC
Power Control Products for all computers.

(r)

V ^ I iS 22

Qt

Eimix

inc.

The Company that delivers

Quality Electronic products since 1975.

1337 WEST 37th PLACE, CHICAGO, IL 60609
(31 2) 927-551 0 • TWX 91 0-221 -4055

242 Microcomputing, October 1980

Call our new toll free number
for further information.

1 - 800 - 255-6638

The Businessman’s
Business System

MSI Business Computer Systems offer flexibility
and expandability unmatched by any other microcom-
puter system, large or small. Our SDOS operating
system is totally device independent and supports up to
four users. This means that you can start with a single
user, dual drive, floppy disk system today, and add up
to 80 megabytes of hard disk with additional worksta-
tions tomorrow. As your business grows, your MSI
system grows with you — and your software won’t be-
come obsolete.

Perform text processing tasks at one workstation
while entering sales orders on another. Add a third
workstation in inventory control and a fourth in ac-
counting. That’s expandability!!!

• MSI Inventory Software, with complete Bills of
Material, provides a complete inventory control and
management system for manufacturers.

• Complete manufacturing forecasting, with produc-
tion pick lists, allows automatic adjustment of compo-
nent inventory levels.

• All transactions resulting in any change to the inven-
tory data base are written to audit trail files listing date,

time, operator’s name, inventory item, and the changes
which were made.

• Sales Order Entry/ Accounts Receivable Software
displays customer balances and credit standing as new
orders are entered. Correct product prices and descrip-
tions are obtained from inventory files if desired.

• Invoices are generated automatically as orders are
shipped. Customer statements, with aged accounts re-
ceivable, are printed on demand.

• Purchase Order Entry/ Accounts Payable Software
optionally link to inventory program, in order to easily
visualize inventory items which are on order.

• General Ledger programs link to the accounts re-
ceivable and accounts payable modules for easy up-
dates and posting.

• If your business is expanding and you would like to
know how an MSI Computer System can help you
make it more profitable, call or write Midwest Scien-
tific Instruments, 220 W. Cedar, Olathe, Kansas
66061, (913) 764-3273, TWX 910 749 6403 (MSI
OLAT), TELEX 42525 (MSI A OLAT).

The Heath H-14 Printer gives you high-performance
features at one of the lowest prices anywhere...

• 5x7 dot matrix and high quality impact printhead
give you clear, easy-to-read images

• Standard 96-character ASCII set, UPPER and lower case

• Operator or software-selectable line widths; 132, 96,
or 80 characters

• Compatibility with any computer having RS-232C or
20 mA current loop serial interface, with handshaking

• Sprocket paper feed, with adjustable spacing, to keep
paper moving smoothly

• Sustainable print speed approximately 30 characters
per second

• "Paper jammed" and “paper out" signals to prevent
loss of data

• Selectable baud rates from 110 to 4800

• Convenience of standard fan-fold paper, 2.5 to 9.5
inches wide

• Chrome wire rack to keep paper neat

Visit your Heathkit
Service Center

H-14 Printers are on display
at the 61 Heathkit Electronic
Centers throughout the U.8.
and Canada. See your telephone
white pages for the location
nearest you.

In the U.S. Heathkit Electronic
Cenfers are units of Veritechnology
Electronics Corporation.

*Inkit form, FOB Benton Harbor, MI. Also available
completely assembled at $895.00, FOB Benton Harbor.
Prices subject to change without notice.

The H-14's remarkable price includes connecting cables,
paper rack, paper, and ribbon — so you're all ready to
run. And service for the H-14 is available at 61 Heathkit
Electronic Centers in the U.S. or Canada.

Check out the microprocessor-based H-14 Printer today,
in kit form or factory assembled. You'll find complete
details in the newest, FREE Heathkit Catalog. Send for
yours today, or pick one up at the nearest Heathkit
Electronic Center. Dealer inquiries on assembled
units are invited, too.

Complete service, so you’re
never left out in the cold

Heatli

Computer Systems

Send for ^236
FREE Catalog

Write to: Heath Company,
Dept. 351-704.

Benton Harbor, ill 1 49032

CP-191